diff --git a/streams/src/main/java/org/apache/kafka/streams/KafkaStreams.java b/streams/src/main/java/org/apache/kafka/streams/KafkaStreams.java
index bf12927bda45c..086ac81083259 100644
--- a/streams/src/main/java/org/apache/kafka/streams/KafkaStreams.java
+++ b/streams/src/main/java/org/apache/kafka/streams/KafkaStreams.java
@@ -48,11 +48,11 @@
 import org.apache.kafka.streams.errors.UnknownStateStoreException;
 import org.apache.kafka.streams.errors.InvalidStateStorePartitionException;
 import org.apache.kafka.streams.internals.metrics.ClientMetrics;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.StateRestoreListener;
 import org.apache.kafka.streams.processor.StateStore;
 import org.apache.kafka.streams.processor.StreamPartitioner;
 import org.apache.kafka.streams.processor.ThreadMetadata;
+import org.apache.kafka.streams.processor.api.Processor;
 import org.apache.kafka.streams.processor.internals.ClientUtils;
 import org.apache.kafka.streams.processor.internals.DefaultKafkaClientSupplier;
 import org.apache.kafka.streams.processor.internals.GlobalStreamThread;
diff --git a/streams/src/main/java/org/apache/kafka/streams/StreamsBuilder.java b/streams/src/main/java/org/apache/kafka/streams/StreamsBuilder.java
index 560b8c89c60be..f270d3e14a3ec 100644
--- a/streams/src/main/java/org/apache/kafka/streams/StreamsBuilder.java
+++ b/streams/src/main/java/org/apache/kafka/streams/StreamsBuilder.java
@@ -487,7 +487,8 @@ public synchronized <K, V> GlobalKTable<K, V> globalTable(final String topic,
     /**
      * Adds a state store to the underlying {@link Topology}.
      * <p>
-     * It is required to connect state stores to {@link org.apache.kafka.streams.processor.Processor Processors}, {@link Transformer Transformers},
+     * It is required to connect state stores to {@link org.apache.kafka.streams.processor.api.Processor Processors},
+     * {@link Transformer Transformers},
      * or {@link ValueTransformer ValueTransformers} before they can be used.
      *
      * @param builder the builder used to obtain this state store {@link StateStore} instance
@@ -515,7 +516,8 @@ public synchronized StreamsBuilder addStateStore(final StoreBuilder<?> builder)
      * This {@link ProcessorNode} should be used to keep the {@link StateStore} up-to-date.
      * The default {@link TimestampExtractor} as specified in the {@link StreamsConfig config} is used.
      * <p>
-     * It is not required to connect a global store to {@link org.apache.kafka.streams.processor.Processor Processors}, {@link Transformer Transformers},
+     * It is not required to connect a global store to {@link org.apache.kafka.streams.processor.api.Processor Processors},
+     * {@link Transformer Transformers},
      * or {@link ValueTransformer ValueTransformer}; those have read-only access to all global stores by default.
      * <p>
      * The supplier should always generate a new instance each time {@link  ProcessorSupplier#get()} gets called. Creating
diff --git a/streams/src/main/java/org/apache/kafka/streams/Topology.java b/streams/src/main/java/org/apache/kafka/streams/Topology.java
index f7cb8d679cb3a..7c45de7f47c9a 100644
--- a/streams/src/main/java/org/apache/kafka/streams/Topology.java
+++ b/streams/src/main/java/org/apache/kafka/streams/Topology.java
@@ -22,11 +22,11 @@
 import org.apache.kafka.streams.kstream.KStream;
 import org.apache.kafka.streams.kstream.KTable;
 import org.apache.kafka.streams.processor.ConnectedStoreProvider;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.StateStore;
 import org.apache.kafka.streams.processor.StreamPartitioner;
 import org.apache.kafka.streams.processor.TimestampExtractor;
 import org.apache.kafka.streams.processor.TopicNameExtractor;
+import org.apache.kafka.streams.processor.api.Processor;
 import org.apache.kafka.streams.processor.api.ProcessorSupplier;
 import org.apache.kafka.streams.processor.internals.InternalTopologyBuilder;
 import org.apache.kafka.streams.processor.internals.ProcessorAdapter;
@@ -655,7 +655,7 @@ public synchronized <K, V> Topology addSink(final String name,
      * will be added to the topology and connected to this processor automatically.
      *
      * @param name the unique name of the processor node
-     * @param supplier the supplier used to obtain this node's {@link Processor} instance
+     * @param supplier the supplier used to obtain this node's {@link org.apache.kafka.streams.processor.Processor} instance
      * @param parentNames the name of one or more source or processor nodes whose output records this processor should receive
      * and process
      * @return itself
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/ForeachAction.java b/streams/src/main/java/org/apache/kafka/streams/kstream/ForeachAction.java
index 42bba28d13b43..f20d77ccb1c71 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/ForeachAction.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/ForeachAction.java
@@ -23,7 +23,7 @@
  * This is a stateless record-by-record operation, i.e, {@link #apply(Object, Object)} is invoked individually for each
  * record of a stream.
  * If stateful processing is required, consider using
- * {@link KStream#process(org.apache.kafka.streams.processor.ProcessorSupplier, String...) KStream#process(...)}.
+ * {@link KStream#process(org.apache.kafka.streams.processor.api.ProcessorSupplier, String...) KStream#process(...)}.
  *
  * @param <K> key type
  * @param <V> value type
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
index 00b9ee8991477..da7aa236b0493 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
@@ -25,9 +25,9 @@
 import org.apache.kafka.streams.StreamsConfig;
 import org.apache.kafka.streams.Topology;
 import org.apache.kafka.streams.processor.ConnectedStoreProvider;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
+import org.apache.kafka.streams.processor.api.Processor;
+import org.apache.kafka.streams.processor.api.ProcessorSupplier;
+import org.apache.kafka.streams.processor.api.ProcessorContext;
 import org.apache.kafka.streams.processor.StreamPartitioner;
 import org.apache.kafka.streams.processor.TopicNameExtractor;
 import org.apache.kafka.streams.state.KeyValueStore;
@@ -3173,12 +3173,13 @@ <GK, GV, RV> KStream<K, RV> leftJoin(final GlobalKTable<GK, GV> globalTable,
      * (cf. {@link #transformValues(ValueTransformerSupplier, String...) transformValues()} )
      * <p>
      * Note that it is possible to emit multiple records for each input record by using
-     * {@link ProcessorContext#forward(Object, Object) context#forward()} in
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) context#forward()} in
      * {@link Transformer#transform(Object, Object) Transformer#transform()} and
      * {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long) Punctuator#punctuate()}.
      * Be aware that a mismatch between the types of the emitted records and the type of the stream would only be
      * detected at runtime.
-     * To ensure type-safety at compile-time, {@link ProcessorContext#forward(Object, Object) context#forward()} should
+     * To ensure type-safety at compile-time,
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) context#forward()} should
      * not be used in {@link Transformer#transform(Object, Object) Transformer#transform()} and
      * {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long) Punctuator#punctuate()}.
      * If in {@link Transformer#transform(Object, Object) Transformer#transform()} multiple records need to be emitted
@@ -3300,12 +3301,13 @@ <K1, V1> KStream<K1, V1> transform(final TransformerSupplier<? super K, ? super
      * (cf. {@link #transformValues(ValueTransformerSupplier, String...) transformValues()} )
      * <p>
      * Note that it is possible to emit multiple records for each input record by using
-     * {@link ProcessorContext#forward(Object, Object) context#forward()} in
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) context#forward()} in
      * {@link Transformer#transform(Object, Object) Transformer#transform()} and
      * {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long) Punctuator#punctuate()}.
      * Be aware that a mismatch between the types of the emitted records and the type of the stream would only be
      * detected at runtime.
-     * To ensure type-safety at compile-time, {@link ProcessorContext#forward(Object, Object) context#forward()} should
+     * To ensure type-safety at compile-time,
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) context#forward()} should
      * not be used in {@link Transformer#transform(Object, Object) Transformer#transform()} and
      * {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long) Punctuator#punctuate()}.
      * If in {@link Transformer#transform(Object, Object) Transformer#transform()} multiple records need to be emitted
@@ -3432,12 +3434,14 @@ <K1, V1> KStream<K1, V1> transform(final TransformerSupplier<? super K, ? super
      * or join) is applied to the result {@code KStream}.
      * (cf. {@link #transformValues(ValueTransformerSupplier, String...) transformValues()})
      * <p>
-     * Note that it is possible to emit records by using {@link ProcessorContext#forward(Object, Object)
+     * Note that it is possible to emit records by using
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object)
      * context#forward()} in {@link Transformer#transform(Object, Object) Transformer#transform()} and
      * {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long) Punctuator#punctuate()}.
      * Be aware that a mismatch between the types of the emitted records and the type of the stream would only be
      * detected at runtime.
-     * To ensure type-safety at compile-time, {@link ProcessorContext#forward(Object, Object) context#forward()} should
+     * To ensure type-safety at compile-time,
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) context#forward()} should
      * not be used in {@link Transformer#transform(Object, Object) Transformer#transform()} and
      * {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long) Punctuator#punctuate()}.
      * The supplier should always generate a new instance each time {@link TransformerSupplier#get()} gets called. Creating
@@ -3558,12 +3562,14 @@ <K1, V1> KStream<K1, V1> flatTransform(final TransformerSupplier<? super K, ? su
      * or join) is applied to the result {@code KStream}.
      * (cf. {@link #transformValues(ValueTransformerSupplier, String...) transformValues()})
      * <p>
-     * Note that it is possible to emit records by using {@link ProcessorContext#forward(Object, Object)
+     * Note that it is possible to emit records by using
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object)
      * context#forward()} in {@link Transformer#transform(Object, Object) Transformer#transform()} and
      * {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long) Punctuator#punctuate()}.
      * Be aware that a mismatch between the types of the emitted records and the type of the stream would only be
      * detected at runtime.
-     * To ensure type-safety at compile-time, {@link ProcessorContext#forward(Object, Object) context#forward()} should
+     * To ensure type-safety at compile-time,
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) context#forward()} should
      * not be used in {@link Transformer#transform(Object, Object) Transformer#transform()} and
      * {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long) Punctuator#punctuate()}.
      * The supplier should always generate a new instance each time {@link TransformerSupplier#get()} gets called. Creating
@@ -3649,7 +3655,8 @@ <K1, V1> KStream<K1, V1> flatTransform(final TransformerSupplier<? super K, ? su
      * a schedule must be registered.
      * The {@link ValueTransformer} must return the new value in {@link ValueTransformer#transform(Object) transform()}.
      * In contrast to {@link #transform(TransformerSupplier, String...) transform()}, no additional {@link KeyValue}
-     * pairs can be emitted via {@link ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
+     * pairs can be emitted via
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
      * A {@link org.apache.kafka.streams.errors.StreamsException} is thrown if the {@link ValueTransformer} tries to
      * emit a {@link KeyValue} pair.
      * <pre>{@code
@@ -3757,7 +3764,8 @@ <VR> KStream<K, VR> transformValues(final ValueTransformerSupplier<? super V, ?
      * a schedule must be registered.
      * The {@link ValueTransformer} must return the new value in {@link ValueTransformer#transform(Object) transform()}.
      * In contrast to {@link #transform(TransformerSupplier, String...) transform()}, no additional {@link KeyValue}
-     * pairs can be emitted via {@link ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
+     * pairs can be emitted via
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
      * A {@link org.apache.kafka.streams.errors.StreamsException} is thrown if the {@link ValueTransformer} tries to
      * emit a {@link KeyValue} pair.
      * <pre>{@code
@@ -3870,7 +3878,8 @@ <VR> KStream<K, VR> transformValues(final ValueTransformerSupplier<? super V, ?
      * {@link ValueTransformerWithKey#transform(Object, Object) transform()}.
      * In contrast to {@link #transform(TransformerSupplier, String...) transform()} and
      * {@link #flatTransform(TransformerSupplier, String...) flatTransform()}, no additional {@link KeyValue} pairs
-     * can be emitted via {@link ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
+     * can be emitted via
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
      * A {@link org.apache.kafka.streams.errors.StreamsException} is thrown if the {@link ValueTransformerWithKey} tries
      * to emit a {@link KeyValue} pair.
      * <pre>{@code
@@ -3982,7 +3991,8 @@ <VR> KStream<K, VR> transformValues(final ValueTransformerWithKeySupplier<? supe
      * {@link ValueTransformerWithKey#transform(Object, Object) transform()}.
      * In contrast to {@link #transform(TransformerSupplier, String...) transform()} and
      * {@link #flatTransform(TransformerSupplier, String...) flatTransform()}, no additional {@link KeyValue} pairs
-     * can be emitted via {@link ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
+     * can be emitted via
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
      * A {@link org.apache.kafka.streams.errors.StreamsException} is thrown if the {@link ValueTransformerWithKey} tries
      * to emit a {@link KeyValue} pair.
      * <pre>{@code
@@ -4099,7 +4109,8 @@ <VR> KStream<K, VR> transformValues(final ValueTransformerWithKeySupplier<? supe
      * {@link java.lang.Iterable Iterable} or {@code null}, no records are emitted.
      * In contrast to {@link #transform(TransformerSupplier, String...) transform()} and
      * {@link #flatTransform(TransformerSupplier, String...) flatTransform()}, no additional {@link KeyValue} pairs
-     * can be emitted via {@link ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
+     * can be emitted via
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
      * A {@link org.apache.kafka.streams.errors.StreamsException} is thrown if the {@link ValueTransformer} tries to
      * emit a {@link KeyValue} pair.
      * <pre>{@code
@@ -4221,7 +4232,8 @@ <VR> KStream<K, VR> flatTransformValues(final ValueTransformerSupplier<? super V
      * {@link java.lang.Iterable Iterable} or {@code null}, no records are emitted.
      * In contrast to {@link #transform(TransformerSupplier, String...) transform()} and
      * {@link #flatTransform(TransformerSupplier, String...) flatTransform()}, no additional {@link KeyValue} pairs
-     * can be emitted via {@link ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
+     * can be emitted via
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
      * A {@link org.apache.kafka.streams.errors.StreamsException} is thrown if the {@link ValueTransformer} tries to
      * emit a {@link KeyValue} pair.
      * <pre>{@code
@@ -4345,7 +4357,8 @@ <VR> KStream<K, VR> flatTransformValues(final ValueTransformerSupplier<? super V
      * is an empty {@link java.lang.Iterable Iterable} or {@code null}, no records are emitted.
      * In contrast to {@link #transform(TransformerSupplier, String...) transform()} and
      * {@link #flatTransform(TransformerSupplier, String...) flatTransform()}, no additional {@link KeyValue} pairs
-     * can be emitted via {@link ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
+     * can be emitted via
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
      * A {@link org.apache.kafka.streams.errors.StreamsException} is thrown if the {@link ValueTransformerWithKey} tries
      * to emit a {@link KeyValue} pair.
      * <pre>{@code
@@ -4468,7 +4481,8 @@ <VR> KStream<K, VR> flatTransformValues(final ValueTransformerWithKeySupplier<?
      * is an empty {@link java.lang.Iterable Iterable} or {@code null}, no records are emitted.
      * In contrast to {@link #transform(TransformerSupplier, String...) transform()} and
      * {@link #flatTransform(TransformerSupplier, String...) flatTransform()}, no additional {@link KeyValue} pairs
-     * can be emitted via {@link ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
+     * can be emitted via
+     * {@link org.apache.kafka.streams.processor.ProcessorContext#forward(Object, Object) ProcessorContext.forward()}.
      * A {@link org.apache.kafka.streams.errors.StreamsException} is thrown if the {@link ValueTransformerWithKey} tries
      * to emit a {@link KeyValue} pair.
      * <pre>{@code
@@ -4524,6 +4538,109 @@ <VR> KStream<K, VR> flatTransformValues(final ValueTransformerWithKeySupplier<?
                                             final Named named,
                                             final String... stateStoreNames);
 
+    /**
+     * Process all records in this stream, one record at a time, by applying a
+     * {@link org.apache.kafka.streams.processor.Processor} (provided by the given
+     * {@link org.apache.kafka.streams.processor.ProcessorSupplier}).
+     * Attaching a state store makes this a stateful record-by-record operation (cf. {@link #foreach(ForeachAction)}).
+     * If you choose not to attach one, this operation is similar to the stateless {@link #foreach(ForeachAction)}
+     * but allows access to the {@code ProcessorContext} and record metadata.
+     * This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI.
+     * Furthermore, via {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long)} the processing progress
+     * can be observed and additional periodic actions can be performed.
+     * Note that this is a terminal operation that returns void.
+     * <p>
+     * In order for the processor to use state stores, the stores must be added to the topology and connected to the
+     * processor using at least one of two strategies (though it's not required to connect global state stores; read-only
+     * access to global state stores is available by default).
+     * <p>
+     * The first strategy is to manually add the {@link StoreBuilder}s via {@link Topology#addStateStore(StoreBuilder, String...)},
+     * and specify the store names via {@code stateStoreNames} so they will be connected to the processor.
+     * <pre>{@code
+     * // create store
+     * StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder =
+     *         Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myProcessorState"),
+     *                 Serdes.String(),
+     *                 Serdes.String());
+     * // add store
+     * builder.addStateStore(keyValueStoreBuilder);
+     *
+     * KStream outputStream = inputStream.processor(new ProcessorSupplier() {
+     *     public Processor get() {
+     *         return new MyProcessor();
+     *     }
+     * }, "myProcessorState");
+     * }</pre>
+     * The second strategy is for the given {@link org.apache.kafka.streams.processor.ProcessorSupplier}
+     * to implement {@link ConnectedStoreProvider#stores()},
+     * which provides the {@link StoreBuilder}s to be automatically added to the topology and connected to the processor.
+     * <pre>{@code
+     * class MyProcessorSupplier implements ProcessorSupplier {
+     *     // supply processor
+     *     Processor get() {
+     *         return new MyProcessor();
+     *     }
+     *
+     *     // provide store(s) that will be added and connected to the associated processor
+     *     // the store name from the builder ("myProcessorState") is used to access the store later via the ProcessorContext
+     *     Set<StoreBuilder> stores() {
+     *         StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder =
+     *                   Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myProcessorState"),
+     *                   Serdes.String(),
+     *                   Serdes.String());
+     *         return Collections.singleton(keyValueStoreBuilder);
+     *     }
+     * }
+     *
+     * ...
+     *
+     * KStream outputStream = inputStream.process(new MyProcessorSupplier());
+     * }</pre>
+     * <p>
+     * With either strategy, within the {@link org.apache.kafka.streams.processor.Processor},
+     * the state is obtained via the {@link org.apache.kafka.streams.processor.ProcessorContext}.
+     * To trigger periodic actions via {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long) punctuate()},
+     * a schedule must be registered.
+     * <pre>{@code
+     * class MyProcessor implements Processor {
+     *     private StateStore state;
+     *
+     *     void init(ProcessorContext context) {
+     *         this.state = context.getStateStore("myProcessorState");
+     *         // punctuate each second, can access this.state
+     *         context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..));
+     *     }
+     *
+     *     void process(K key, V value) {
+     *         // can access this.state
+     *     }
+     *
+     *     void close() {
+     *         // can access this.state
+     *     }
+     * }
+     * }</pre>
+     * Even if any upstream operation was key-changing, no auto-repartition is triggered.
+     * If repartitioning is required, a call to {@link #repartition()} should be performed before {@code process()}.
+     *
+     * @param processorSupplier an instance of {@link org.apache.kafka.streams.processor.ProcessorSupplier}
+     *                          that generates a newly constructed {@link org.apache.kafka.streams.processor.Processor}
+     *                          The supplier should always generate a new instance. Creating a single
+     *                          {@link org.apache.kafka.streams.processor.Processor} object
+     *                          and returning the same object reference in
+     *                          {@link org.apache.kafka.streams.processor.ProcessorSupplier#get()} is a
+     *                          violation of the supplier pattern and leads to runtime exceptions.
+     * @param stateStoreNames     the names of the state stores used by the processor; not required if the supplier
+     *                            implements {@link ConnectedStoreProvider#stores()}
+     * @see #foreach(ForeachAction)
+     * @see #transform(TransformerSupplier, String...)
+     * @deprecated Since 3.0. Use {@link KStream#process(org.apache.kafka.streams.processor.api.ProcessorSupplier, java.lang.String...)} instead.
+     */
+    @Deprecated
+    void process(final org.apache.kafka.streams.processor.ProcessorSupplier<? super K, ? super V> processorSupplier,
+                 final String... stateStoreNames);
+
+
     /**
      * Process all records in this stream, one record at a time, by applying a {@link Processor} (provided by the given
      * {@link ProcessorSupplier}).
@@ -4615,7 +4732,110 @@ <VR> KStream<K, VR> flatTransformValues(final ValueTransformerWithKeySupplier<?
      * @see #foreach(ForeachAction)
      * @see #transform(TransformerSupplier, String...)
      */
-    void process(final ProcessorSupplier<? super K, ? super V> processorSupplier,
+    void process(final ProcessorSupplier<? super K, ? super V, Void, Void> processorSupplier,
+                 final String... stateStoreNames);
+
+    /**
+     * Process all records in this stream, one record at a time, by applying a
+     * {@link org.apache.kafka.streams.processor.Processor} (provided by the given
+     * {@link org.apache.kafka.streams.processor.ProcessorSupplier}).
+     * Attaching a state store makes this a stateful record-by-record operation (cf. {@link #foreach(ForeachAction)}).
+     * If you choose not to attach one, this operation is similar to the stateless {@link #foreach(ForeachAction)}
+     * but allows access to the {@code ProcessorContext} and record metadata.
+     * This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI.
+     * Furthermore, via {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long)} the processing progress
+     * can be observed and additional periodic actions can be performed.
+     * Note that this is a terminal operation that returns void.
+     * <p>
+     * In order for the processor to use state stores, the stores must be added to the topology and connected to the
+     * processor using at least one of two strategies (though it's not required to connect global state stores; read-only
+     * access to global state stores is available by default).
+     * <p>
+     * The first strategy is to manually add the {@link StoreBuilder}s via {@link Topology#addStateStore(StoreBuilder, String...)},
+     * and specify the store names via {@code stateStoreNames} so they will be connected to the processor.
+     * <pre>{@code
+     * // create store
+     * StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder =
+     *         Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myProcessorState"),
+     *                 Serdes.String(),
+     *                 Serdes.String());
+     * // add store
+     * builder.addStateStore(keyValueStoreBuilder);
+     *
+     * KStream outputStream = inputStream.processor(new ProcessorSupplier() {
+     *     public Processor get() {
+     *         return new MyProcessor();
+     *     }
+     * }, "myProcessorState");
+     * }</pre>
+     * The second strategy is for the given {@link org.apache.kafka.streams.processor.ProcessorSupplier}
+     * to implement {@link ConnectedStoreProvider#stores()},
+     * which provides the {@link StoreBuilder}s to be automatically added to the topology and connected to the processor.
+     * <pre>{@code
+     * class MyProcessorSupplier implements ProcessorSupplier {
+     *     // supply processor
+     *     Processor get() {
+     *         return new MyProcessor();
+     *     }
+     *
+     *     // provide store(s) that will be added and connected to the associated processor
+     *     // the store name from the builder ("myProcessorState") is used to access the store later via the ProcessorContext
+     *     Set<StoreBuilder> stores() {
+     *         StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder =
+     *                   Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myProcessorState"),
+     *                   Serdes.String(),
+     *                   Serdes.String());
+     *         return Collections.singleton(keyValueStoreBuilder);
+     *     }
+     * }
+     *
+     * ...
+     *
+     * KStream outputStream = inputStream.process(new MyProcessorSupplier());
+     * }</pre>
+     * <p>
+     * With either strategy, within the {@link org.apache.kafka.streams.processor.Processor},
+     * the state is obtained via the {@link org.apache.kafka.streams.processor.ProcessorContext}.
+     * To trigger periodic actions via {@link org.apache.kafka.streams.processor.Punctuator#punctuate(long) punctuate()},
+     * a schedule must be registered.
+     * <pre>{@code
+     * class MyProcessor implements Processor {
+     *     private StateStore state;
+     *
+     *     void init(ProcessorContext context) {
+     *         this.state = context.getStateStore("myProcessorState");
+     *         // punctuate each second, can access this.state
+     *         context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..));
+     *     }
+     *
+     *     void process(K key, V value) {
+     *         // can access this.state
+     *     }
+     *
+     *     void close() {
+     *         // can access this.state
+     *     }
+     * }
+     * }</pre>
+     * Even if any upstream operation was key-changing, no auto-repartition is triggered.
+     * If repartitioning is required, a call to {@link #repartition()} should be performed before {@code process()}.
+     *
+     * @param processorSupplier an instance of {@link org.apache.kafka.streams.processor.ProcessorSupplier}
+     *                          that generates a newly constructed {@link org.apache.kafka.streams.processor.Processor}
+     *                          The supplier should always generate a new instance. Creating a single
+     *                          {@link org.apache.kafka.streams.processor.Processor} object
+     *                          and returning the same object reference in
+     *                          {@link org.apache.kafka.streams.processor.ProcessorSupplier#get()} is a
+     *                          violation of the supplier pattern and leads to runtime exceptions.
+     * @param named             a {@link Named} config used to name the processor in the topology
+     * @param stateStoreNames   the names of the state store used by the processor
+     * @see #foreach(ForeachAction)
+     * @see #transform(TransformerSupplier, String...)
+     * @deprecated Since 3.0. Use {@link KStream#process(org.apache.kafka.streams.processor.api.ProcessorSupplier, org.apache.kafka.streams.kstream.Named, java.lang.String...)} instead.
+     */
+    @Deprecated
+    void process(final org.apache.kafka.streams.processor.ProcessorSupplier<? super K, ? super V> processorSupplier,
+                 final Named named,
                  final String... stateStoreNames);
 
     /**
@@ -4709,7 +4929,7 @@ void process(final ProcessorSupplier<? super K, ? super V> processorSupplier,
      * @see #foreach(ForeachAction)
      * @see #transform(TransformerSupplier, String...)
      */
-    void process(final ProcessorSupplier<? super K, ? super V> processorSupplier,
+    void process(final ProcessorSupplier<? super K, ? super V, Void, Void> processorSupplier,
                  final Named named,
                  final String... stateStoreNames);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CogroupedStreamAggregateBuilder.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CogroupedStreamAggregateBuilder.java
index c7585263a718a..80d9215460d61 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CogroupedStreamAggregateBuilder.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CogroupedStreamAggregateBuilder.java
@@ -38,7 +38,6 @@
 import org.apache.kafka.streams.kstream.internals.graph.ProcessorParameters;
 import org.apache.kafka.streams.kstream.internals.graph.StatefulProcessorNode;
 import org.apache.kafka.streams.kstream.internals.graph.GraphNode;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.state.StoreBuilder;
 
 class CogroupedStreamAggregateBuilder<K, VOut> {
@@ -255,10 +254,11 @@ <KR, VIn> KTable<KR, VOut> createTable(final Collection<GraphNode> processors,
             builder);
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     private StatefulProcessorNode<K, ?> getStatefulProcessorNode(final String processorName,
                                                                  final boolean stateCreated,
                                                                  final StoreBuilder<?> storeBuilder,
-                                                                 final ProcessorSupplier<K, ?> kStreamAggregate) {
+                                                                 final org.apache.kafka.streams.processor.ProcessorSupplier<K, ?> kStreamAggregate) {
         final StatefulProcessorNode<K, ?> statefulProcessorNode;
         if (!stateCreated) {
             statefulProcessorNode =
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KGroupedTableImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KGroupedTableImpl.java
index 4dde9c126c033..111d16968c4f8 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KGroupedTableImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KGroupedTableImpl.java
@@ -29,7 +29,6 @@
 import org.apache.kafka.streams.kstream.internals.graph.ProcessorParameters;
 import org.apache.kafka.streams.kstream.internals.graph.StatefulProcessorNode;
 import org.apache.kafka.streams.kstream.internals.graph.GraphNode;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.state.KeyValueStore;
 
 import java.util.Collections;
@@ -68,7 +67,8 @@ public class KGroupedTableImpl<K, V> extends AbstractStream<K, V> implements KGr
         this.userProvidedRepartitionTopicName = groupedInternal.name();
     }
 
-    private <T> KTable<K, T> doAggregate(final ProcessorSupplier<K, Change<V>> aggregateSupplier,
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private <T> KTable<K, T> doAggregate(final org.apache.kafka.streams.processor.ProcessorSupplier<K, Change<V>> aggregateSupplier,
                                          final NamedInternal named,
                                          final String functionName,
                                          final MaterializedInternal<K, T, KeyValueStore<Bytes, byte[]>> materialized) {
@@ -145,7 +145,8 @@ public KTable<K, V> reduce(final Reducer<V> adder,
         if (materializedInternal.valueSerde() == null) {
             materializedInternal.withValueSerde(valueSerde);
         }
-        final ProcessorSupplier<K, Change<V>> aggregateSupplier = new KTableReduce<>(
+        @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+        final org.apache.kafka.streams.processor.ProcessorSupplier<K, Change<V>> aggregateSupplier = new KTableReduce<>(
             materializedInternal.storeName(),
             adder,
             subtractor);
@@ -176,7 +177,8 @@ public KTable<K, Long> count(final Named named, final Materialized<K, Long, KeyV
             materializedInternal.withValueSerde(Serdes.Long());
         }
 
-        final ProcessorSupplier<K, Change<V>> aggregateSupplier = new KTableAggregate<>(
+        @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+        final org.apache.kafka.streams.processor.ProcessorSupplier<K, Change<V>> aggregateSupplier = new KTableAggregate<>(
             materializedInternal.storeName(),
             countInitializer,
             countAdder,
@@ -221,7 +223,8 @@ public <VR> KTable<K, VR> aggregate(final Initializer<VR> initializer,
         if (materializedInternal.keySerde() == null) {
             materializedInternal.withKeySerde(keySerde);
         }
-        final ProcessorSupplier<K, Change<V>> aggregateSupplier = new KTableAggregate<>(
+        @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+        final org.apache.kafka.streams.processor.ProcessorSupplier<K, Change<V>> aggregateSupplier = new KTableAggregate<>(
             materializedInternal.storeName(),
             initializer,
             adder,
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamAggProcessorSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamAggProcessorSupplier.java
index 3f2186052371b..fab61be089ffb 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamAggProcessorSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamAggProcessorSupplier.java
@@ -16,9 +16,8 @@
  */
 package org.apache.kafka.streams.kstream.internals;
 
-import org.apache.kafka.streams.processor.ProcessorSupplier;
-
-public interface KStreamAggProcessorSupplier<K, RK, V, T> extends ProcessorSupplier<K, V> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public interface KStreamAggProcessorSupplier<K, RK, V, T> extends org.apache.kafka.streams.processor.ProcessorSupplier<K, V> {
 
     KTableValueGetterSupplier<RK, T> view();
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamAggregate.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamAggregate.java
index 4397fbc429d55..0f83849e37621 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamAggregate.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamAggregate.java
@@ -19,9 +19,6 @@
 import org.apache.kafka.common.metrics.Sensor;
 import org.apache.kafka.streams.kstream.Aggregator;
 import org.apache.kafka.streams.kstream.Initializer;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.TimestampedKeyValueStore;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
@@ -31,6 +28,7 @@
 import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamAggregate<K, V, T> implements KStreamAggProcessorSupplier<K, K, V, T> {
     private static final Logger LOG = LoggerFactory.getLogger(KStreamAggregate.class);
     private final String storeName;
@@ -48,7 +46,7 @@ public class KStreamAggregate<K, V, T> implements KStreamAggProcessorSupplier<K,
     }
 
     @Override
-    public Processor<K, V> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V> get() {
         return new KStreamAggregateProcessor();
     }
 
@@ -58,13 +56,13 @@ public void enableSendingOldValues() {
     }
 
 
-    private class KStreamAggregateProcessor extends AbstractProcessor<K, V> {
+    private class KStreamAggregateProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, V> {
         private TimestampedKeyValueStore<K, T> store;
         private Sensor droppedRecordsSensor;
         private TimestampedTupleForwarder<K, T> tupleForwarder;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             droppedRecordsSensor = droppedRecordsSensor(
                 Thread.currentThread().getName(),
@@ -130,7 +128,7 @@ private class KStreamAggregateValueGetter implements KTableValueGetter<K, T> {
         private TimestampedKeyValueStore<K, T> store;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             store = context.getStateStore(storeName);
         }
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransform.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransform.java
index 7836d440d372a..4d4fd2bf4740d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransform.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransform.java
@@ -19,15 +19,12 @@
 import org.apache.kafka.streams.KeyValue;
 import org.apache.kafka.streams.kstream.Transformer;
 import org.apache.kafka.streams.kstream.TransformerSupplier;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.state.StoreBuilder;
 
 import java.util.Set;
 
-public class KStreamFlatTransform<KIn, VIn, KOut, VOut> implements ProcessorSupplier<KIn, VIn> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public class KStreamFlatTransform<KIn, VIn, KOut, VOut> implements org.apache.kafka.streams.processor.ProcessorSupplier<KIn, VIn> {
 
     private final TransformerSupplier<? super KIn, ? super VIn, Iterable<KeyValue<KOut, VOut>>> transformerSupplier;
 
@@ -36,7 +33,7 @@ public KStreamFlatTransform(final TransformerSupplier<? super KIn, ? super VIn,
     }
 
     @Override
-    public Processor<KIn, VIn> get() {
+    public org.apache.kafka.streams.processor.Processor<KIn, VIn> get() {
         return new KStreamFlatTransformProcessor<>(transformerSupplier.get());
     }
 
@@ -45,7 +42,7 @@ public Set<StoreBuilder<?>> stores() {
         return transformerSupplier.stores();
     }
 
-    public static class KStreamFlatTransformProcessor<KIn, VIn, KOut, VOut> extends AbstractProcessor<KIn, VIn> {
+    public static class KStreamFlatTransformProcessor<KIn, VIn, KOut, VOut> extends org.apache.kafka.streams.processor.AbstractProcessor<KIn, VIn> {
 
         private final Transformer<? super KIn, ? super VIn, Iterable<KeyValue<KOut, VOut>>> transformer;
 
@@ -54,7 +51,7 @@ public KStreamFlatTransformProcessor(final Transformer<? super KIn, ? super VIn,
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             transformer.init(context);
         }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformValues.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformValues.java
index 62955951bdf51..baf44c752a49e 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformValues.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformValues.java
@@ -18,16 +18,13 @@
 
 import org.apache.kafka.streams.kstream.ValueTransformerWithKey;
 import org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.processor.internals.ForwardingDisabledProcessorContext;
 import org.apache.kafka.streams.state.StoreBuilder;
 
 import java.util.Set;
 
-public class KStreamFlatTransformValues<KIn, VIn, VOut> implements ProcessorSupplier<KIn, VIn> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public class KStreamFlatTransformValues<KIn, VIn, VOut> implements org.apache.kafka.streams.processor.ProcessorSupplier<KIn, VIn> {
 
     private final ValueTransformerWithKeySupplier<KIn, VIn, Iterable<VOut>> valueTransformerSupplier;
 
@@ -36,7 +33,7 @@ public KStreamFlatTransformValues(final ValueTransformerWithKeySupplier<KIn, VIn
     }
 
     @Override
-    public Processor<KIn, VIn> get() {
+    public org.apache.kafka.streams.processor.Processor<KIn, VIn> get() {
         return new KStreamFlatTransformValuesProcessor<>(valueTransformerSupplier.get());
     }
 
@@ -45,7 +42,7 @@ public Set<StoreBuilder<?>> stores() {
         return valueTransformerSupplier.stores();
     }
 
-    public static class KStreamFlatTransformValuesProcessor<KIn, VIn, VOut> extends AbstractProcessor<KIn, VIn> {
+    public static class KStreamFlatTransformValuesProcessor<KIn, VIn, VOut> extends org.apache.kafka.streams.processor.AbstractProcessor<KIn, VIn> {
 
         private final ValueTransformerWithKey<KIn, VIn, Iterable<VOut>> valueTransformer;
 
@@ -54,7 +51,7 @@ public static class KStreamFlatTransformValuesProcessor<KIn, VIn, VOut> extends
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             valueTransformer.init(new ForwardingDisabledProcessorContext(context));
         }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableJoin.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableJoin.java
index 568a639efeb53..be3fe6b343f47 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableJoin.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableJoin.java
@@ -18,10 +18,9 @@
 
 import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.ValueJoinerWithKey;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 
-class KStreamGlobalKTableJoin<K1, K2, R, V1, V2> implements ProcessorSupplier<K1, V1> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+class KStreamGlobalKTableJoin<K1, K2, R, V1, V2> implements org.apache.kafka.streams.processor.ProcessorSupplier<K1, V1> {
 
     private final KTableValueGetterSupplier<K2, V2> valueGetterSupplier;
     private final ValueJoinerWithKey<? super K1, ? super V1, ? super V2, ? extends R> joiner;
@@ -39,7 +38,7 @@ class KStreamGlobalKTableJoin<K1, K2, R, V1, V2> implements ProcessorSupplier<K1
     }
 
     @Override
-    public Processor<K1, V1> get() {
+    public org.apache.kafka.streams.processor.Processor<K1, V1> get() {
         return new KStreamKTableJoinProcessor<>(valueGetterSupplier.get(), mapper, joiner, leftJoin);
     }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
index 7ac688108970d..f7075f6bb139c 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
@@ -58,7 +58,7 @@
 import org.apache.kafka.streams.kstream.internals.graph.UnoptimizableRepartitionNode;
 import org.apache.kafka.streams.kstream.internals.graph.UnoptimizableRepartitionNode.UnoptimizableRepartitionNodeBuilder;
 import org.apache.kafka.streams.processor.FailOnInvalidTimestamp;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
+import org.apache.kafka.streams.processor.api.ProcessorSupplier;
 import org.apache.kafka.streams.processor.StreamPartitioner;
 import org.apache.kafka.streams.processor.TopicNameExtractor;
 import org.apache.kafka.streams.kstream.ForeachProcessor;
@@ -1215,7 +1215,9 @@ private <KG, VG, VR> KStream<K, VR> globalTableJoin(final GlobalKTable<KG, VG> g
         final KTableValueGetterSupplier<KG, VG> valueGetterSupplier =
             ((GlobalKTableImpl<KG, VG>) globalTable).valueGetterSupplier();
         final String name = new NamedInternal(named).orElseGenerateWithPrefix(builder, LEFTJOIN_NAME);
-        final ProcessorSupplier<K, V> processorSupplier = new KStreamGlobalKTableJoin<>(
+        // Old PAPI. Needs to be migrated.
+        @SuppressWarnings("deprecation")
+        final org.apache.kafka.streams.processor.ProcessorSupplier<K, V> processorSupplier = new KStreamGlobalKTableJoin<>(
             valueGetterSupplier,
             joiner,
             keySelector,
@@ -1251,7 +1253,9 @@ private <VO, VR> KStream<K, VR> doStreamTableJoin(final KTable<K, VO> table,
         final NamedInternal renamed = new NamedInternal(joinedInternal.name());
 
         final String name = renamed.orElseGenerateWithPrefix(builder, leftJoin ? LEFTJOIN_NAME : JOIN_NAME);
-        final ProcessorSupplier<K, V> processorSupplier = new KStreamKTableJoin<>(
+        // Old PAPI. Needs to be migrated.
+        @SuppressWarnings("deprecation")
+        final org.apache.kafka.streams.processor.ProcessorSupplier<K, V> processorSupplier = new KStreamKTableJoin<>(
             ((KTableImpl<K, ?, VO>) table).valueGetterSupplier(),
             joiner,
             leftJoin);
@@ -1466,13 +1470,42 @@ private <VR> KStream<K, VR> doFlatTransformValues(final ValueTransformerWithKeyS
     }
 
     @Override
-    public void process(final ProcessorSupplier<? super K, ? super V> processorSupplier,
+    @Deprecated
+    public void process(final org.apache.kafka.streams.processor.ProcessorSupplier<? super K, ? super V> processorSupplier,
                         final String... stateStoreNames) {
         process(processorSupplier, Named.as(builder.newProcessorName(PROCESSOR_NAME)), stateStoreNames);
     }
 
     @Override
-    public void process(final ProcessorSupplier<? super K, ? super V> processorSupplier,
+    public void process(final ProcessorSupplier<? super K, ? super V, Void, Void> processorSupplier,
+                        final String... stateStoreNames) {
+        process(processorSupplier, Named.as(builder.newProcessorName(PROCESSOR_NAME)), stateStoreNames);
+    }
+
+    @Override
+    @Deprecated
+    public void process(final org.apache.kafka.streams.processor.ProcessorSupplier<? super K, ? super V> processorSupplier,
+                        final Named named,
+                        final String... stateStoreNames) {
+        Objects.requireNonNull(processorSupplier, "processorSupplier can't be null");
+        Objects.requireNonNull(named, "named can't be null");
+        Objects.requireNonNull(stateStoreNames, "stateStoreNames can't be a null array");
+        ApiUtils.checkSupplier(processorSupplier);
+        for (final String stateStoreName : stateStoreNames) {
+            Objects.requireNonNull(stateStoreName, "stateStoreNames can't be null");
+        }
+
+        final String name = new NamedInternal(named).name();
+        final StatefulProcessorNode<? super K, ? super V> processNode = new StatefulProcessorNode<>(
+            name,
+            new ProcessorParameters<>(processorSupplier, name),
+            stateStoreNames);
+
+        builder.addGraphNode(graphNode, processNode);
+    }
+
+    @Override
+    public void process(final ProcessorSupplier<? super K, ? super V, Void, Void> processorSupplier,
                         final Named named,
                         final String... stateStoreNames) {
         Objects.requireNonNull(processorSupplier, "processorSupplier can't be null");
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamJoinWindow.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamJoinWindow.java
index 34756d47cf2ee..87edbbc2c2748 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamJoinWindow.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamJoinWindow.java
@@ -16,13 +16,10 @@
  */
 package org.apache.kafka.streams.kstream.internals;
 
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.state.WindowStore;
 
-class KStreamJoinWindow<K, V> implements ProcessorSupplier<K, V> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+class KStreamJoinWindow<K, V> implements org.apache.kafka.streams.processor.ProcessorSupplier<K, V> {
 
     private final String windowName;
 
@@ -31,17 +28,17 @@ class KStreamJoinWindow<K, V> implements ProcessorSupplier<K, V> {
     }
 
     @Override
-    public Processor<K, V> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V> get() {
         return new KStreamJoinWindowProcessor();
     }
 
-    private class KStreamJoinWindowProcessor extends AbstractProcessor<K, V> {
+    private class KStreamJoinWindowProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, V> {
 
         private WindowStore<K, V> window;
 
         @SuppressWarnings("unchecked")
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
 
             window = (WindowStore<K, V>) context.getStateStore(windowName);
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoin.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoin.java
index 52853fbbdaa41..fcf1cf944944d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoin.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoin.java
@@ -21,10 +21,6 @@
 import org.apache.kafka.streams.StreamsConfig;
 import org.apache.kafka.streams.kstream.ValueJoinerWithKey;
 import org.apache.kafka.streams.kstream.Windowed;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.processor.To;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.KeyValueIterator;
@@ -40,7 +36,8 @@
 import static org.apache.kafka.streams.StreamsConfig.InternalConfig.ENABLE_KSTREAMS_OUTER_JOIN_SPURIOUS_RESULTS_FIX;
 import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
 
-class KStreamKStreamJoin<K, R, V1, V2> implements ProcessorSupplier<K, V1> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+class KStreamKStreamJoin<K, R, V1, V2> implements org.apache.kafka.streams.processor.ProcessorSupplier<K, V1> {
     private static final Logger LOG = LoggerFactory.getLogger(KStreamKStreamJoin.class);
 
     private final String otherWindowName;
@@ -76,17 +73,17 @@ class KStreamKStreamJoin<K, R, V1, V2> implements ProcessorSupplier<K, V1> {
     }
 
     @Override
-    public Processor<K, V1> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V1> get() {
         return new KStreamKStreamJoinProcessor();
     }
 
-    private class KStreamKStreamJoinProcessor extends AbstractProcessor<K, V1> {
+    private class KStreamKStreamJoinProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, V1> {
         private WindowStore<K, V2> otherWindowStore;
         private Sensor droppedRecordsSensor;
         private Optional<WindowStore<KeyAndJoinSide<K>, LeftOrRightValue>> outerJoinWindowStore = Optional.empty();
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             final StreamsMetricsImpl metrics = (StreamsMetricsImpl) context.metrics();
             droppedRecordsSensor = droppedRecordsSensor(Thread.currentThread().getName(), context.taskId().toString(), metrics);
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoin.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoin.java
index 136b953441b29..deca86d21b3ec 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoin.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoin.java
@@ -18,10 +18,9 @@
 
 import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.ValueJoinerWithKey;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 
-class KStreamKTableJoin<K, R, V1, V2> implements ProcessorSupplier<K, V1> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+class KStreamKTableJoin<K, R, V1, V2> implements org.apache.kafka.streams.processor.ProcessorSupplier<K, V1> {
 
     private final KeyValueMapper<K, V1, K> keyValueMapper = (key, value) -> key;
     private final KTableValueGetterSupplier<K, V2> valueGetterSupplier;
@@ -37,7 +36,7 @@ class KStreamKTableJoin<K, R, V1, V2> implements ProcessorSupplier<K, V1> {
     }
 
     @Override
-    public Processor<K, V1> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V1> get() {
         return new KStreamKTableJoinProcessor<>(valueGetterSupplier.get(), keyValueMapper, joiner, leftJoin);
     }
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoinProcessor.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoinProcessor.java
index 29c49e8915cff..38e839c130795 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoinProcessor.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoinProcessor.java
@@ -19,8 +19,6 @@
 import org.apache.kafka.common.metrics.Sensor;
 import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.ValueJoinerWithKey;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -28,7 +26,8 @@
 import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
-class KStreamKTableJoinProcessor<K1, K2, V1, V2, R> extends AbstractProcessor<K1, V1> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+class KStreamKTableJoinProcessor<K1, K2, V1, V2, R> extends org.apache.kafka.streams.processor.AbstractProcessor<K1, V1> {
     private static final Logger LOG = LoggerFactory.getLogger(KStreamKTableJoin.class);
 
     private final KTableValueGetter<K2, V2> valueGetter;
@@ -48,7 +47,7 @@ class KStreamKTableJoinProcessor<K1, K2, V1, V2, R> extends AbstractProcessor<K1
     }
 
     @Override
-    public void init(final ProcessorContext context) {
+    public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
         super.init(context);
         final StreamsMetricsImpl metrics = (StreamsMetricsImpl) context.metrics();
         droppedRecordsSensor = droppedRecordsSensor(Thread.currentThread().getName(), context.taskId().toString(), metrics);
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamReduce.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamReduce.java
index bf25ff6d7a15c..d774217822792 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamReduce.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamReduce.java
@@ -18,9 +18,6 @@
 
 import org.apache.kafka.common.metrics.Sensor;
 import org.apache.kafka.streams.kstream.Reducer;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.TimestampedKeyValueStore;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
@@ -30,6 +27,7 @@
 import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamReduce<K, V> implements KStreamAggProcessorSupplier<K, K, V, V> {
     private static final Logger LOG = LoggerFactory.getLogger(KStreamReduce.class);
 
@@ -44,7 +42,7 @@ public class KStreamReduce<K, V> implements KStreamAggProcessorSupplier<K, K, V,
     }
 
     @Override
-    public Processor<K, V> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V> get() {
         return new KStreamReduceProcessor();
     }
 
@@ -54,13 +52,13 @@ public void enableSendingOldValues() {
     }
 
 
-    private class KStreamReduceProcessor extends AbstractProcessor<K, V> {
+    private class KStreamReduceProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, V> {
         private TimestampedKeyValueStore<K, V> store;
         private TimestampedTupleForwarder<K, V> tupleForwarder;
         private Sensor droppedRecordsSensor;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             droppedRecordsSensor = droppedRecordsSensor(
                 Thread.currentThread().getName(),
@@ -126,7 +124,7 @@ private class KStreamReduceValueGetter implements KTableValueGetter<K, V> {
         private TimestampedKeyValueStore<K, V> store;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             store = context.getStateStore(storeName);
         }
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamSessionWindowAggregate.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamSessionWindowAggregate.java
index 413d6ca1098f5..a2fce1edf4ac1 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamSessionWindowAggregate.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamSessionWindowAggregate.java
@@ -24,9 +24,6 @@
 import org.apache.kafka.streams.kstream.Merger;
 import org.apache.kafka.streams.kstream.SessionWindows;
 import org.apache.kafka.streams.kstream.Windowed;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.KeyValueIterator;
 import org.apache.kafka.streams.state.SessionStore;
@@ -39,6 +36,7 @@
 
 import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamSessionWindowAggregate<K, V, Agg> implements KStreamAggProcessorSupplier<K, Windowed<K>, V, Agg> {
     private static final Logger LOG = LoggerFactory.getLogger(KStreamSessionWindowAggregate.class);
 
@@ -63,7 +61,7 @@ public KStreamSessionWindowAggregate(final SessionWindows windows,
     }
 
     @Override
-    public Processor<K, V> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V> get() {
         return new KStreamSessionWindowAggregateProcessor();
     }
 
@@ -76,7 +74,7 @@ public void enableSendingOldValues() {
         sendOldValues = true;
     }
 
-    private class KStreamSessionWindowAggregateProcessor extends AbstractProcessor<K, V> {
+    private class KStreamSessionWindowAggregateProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, V> {
 
         private SessionStore<K, Agg> store;
         private SessionTupleForwarder<K, Agg> tupleForwarder;
@@ -85,7 +83,7 @@ private class KStreamSessionWindowAggregateProcessor extends AbstractProcessor<K
         private long observedStreamTime = ConsumerRecord.NO_TIMESTAMP;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             final StreamsMetricsImpl metrics = (StreamsMetricsImpl) context.metrics();
             final String threadId = Thread.currentThread().getName();
@@ -199,7 +197,7 @@ private class KTableSessionWindowValueGetter implements KTableValueGetter<Window
         private SessionStore<K, Agg> store;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             store = context.getStateStore(storeName);
         }
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamSlidingWindowAggregate.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamSlidingWindowAggregate.java
index c3ae7ceae0f48..64b747a9ab342 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamSlidingWindowAggregate.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamSlidingWindowAggregate.java
@@ -24,9 +24,6 @@
 import org.apache.kafka.streams.kstream.Window;
 import org.apache.kafka.streams.kstream.Windowed;
 import org.apache.kafka.streams.kstream.SlidingWindows;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.InternalProcessorContext;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.KeyValueIterator;
@@ -40,6 +37,7 @@
 import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamSlidingWindowAggregate<K, V, Agg> implements KStreamAggProcessorSupplier<K, Windowed<K>, V, Agg> {
     private final Logger log = LoggerFactory.getLogger(getClass());
 
@@ -61,7 +59,7 @@ public KStreamSlidingWindowAggregate(final SlidingWindows windows,
     }
 
     @Override
-    public Processor<K, V> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V> get() {
         return new KStreamSlidingWindowAggregateProcessor();
     }
 
@@ -74,7 +72,7 @@ public void enableSendingOldValues() {
         sendOldValues = true;
     }
 
-    private class KStreamSlidingWindowAggregateProcessor extends AbstractProcessor<K, V> {
+    private class KStreamSlidingWindowAggregateProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, V> {
         private TimestampedWindowStore<K, Agg> windowStore;
         private TimestampedTupleForwarder<Windowed<K>, Agg> tupleForwarder;
         private Sensor lateRecordDropSensor;
@@ -83,7 +81,7 @@ private class KStreamSlidingWindowAggregateProcessor extends AbstractProcessor<K
         private Boolean reverseIteratorPossible = null;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             final InternalProcessorContext internalProcessorContext = (InternalProcessorContext) context;
             final StreamsMetricsImpl metrics = internalProcessorContext.metrics();
@@ -519,7 +517,7 @@ private class KStreamWindowAggregateValueGetter implements KTableValueGetter<Win
         private TimestampedWindowStore<K, Agg> windowStore;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             windowStore = context.getStateStore(storeName);
         }
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValues.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValues.java
index e2be315e0c142..468bf8dfa2b8b 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValues.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValues.java
@@ -18,16 +18,13 @@
 
 import org.apache.kafka.streams.kstream.ValueTransformerWithKey;
 import org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.processor.internals.ForwardingDisabledProcessorContext;
 import org.apache.kafka.streams.state.StoreBuilder;
 
 import java.util.Set;
 
-public class KStreamTransformValues<K, V, R> implements ProcessorSupplier<K, V> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public class KStreamTransformValues<K, V, R> implements org.apache.kafka.streams.processor.ProcessorSupplier<K, V> {
 
     private final ValueTransformerWithKeySupplier<K, V, R> valueTransformerSupplier;
 
@@ -36,7 +33,7 @@ public class KStreamTransformValues<K, V, R> implements ProcessorSupplier<K, V>
     }
 
     @Override
-    public Processor<K, V> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V> get() {
         return new KStreamTransformValuesProcessor<>(valueTransformerSupplier.get());
     }
 
@@ -45,7 +42,7 @@ public Set<StoreBuilder<?>> stores() {
         return valueTransformerSupplier.stores();
     }
 
-    public static class KStreamTransformValuesProcessor<K, V, R> extends AbstractProcessor<K, V> {
+    public static class KStreamTransformValuesProcessor<K, V, R> extends org.apache.kafka.streams.processor.AbstractProcessor<K, V> {
 
         private final ValueTransformerWithKey<K, V, R> valueTransformer;
 
@@ -54,7 +51,7 @@ public static class KStreamTransformValuesProcessor<K, V, R> extends AbstractPro
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             valueTransformer.init(new ForwardingDisabledProcessorContext(context));
         }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindowAggregate.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindowAggregate.java
index 300f3872e4d3f..174158dc77a11 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindowAggregate.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindowAggregate.java
@@ -23,9 +23,6 @@
 import org.apache.kafka.streams.kstream.Window;
 import org.apache.kafka.streams.kstream.Windowed;
 import org.apache.kafka.streams.kstream.Windows;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.InternalProcessorContext;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.TimestampedWindowStore;
@@ -38,6 +35,7 @@
 import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamWindowAggregate<K, V, Agg, W extends Window> implements KStreamAggProcessorSupplier<K, Windowed<K>, V, Agg> {
     private final Logger log = LoggerFactory.getLogger(getClass());
 
@@ -59,7 +57,7 @@ public KStreamWindowAggregate(final Windows<W> windows,
     }
 
     @Override
-    public Processor<K, V> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V> get() {
         return new KStreamWindowAggregateProcessor();
     }
 
@@ -73,7 +71,7 @@ public void enableSendingOldValues() {
     }
 
 
-    private class KStreamWindowAggregateProcessor extends AbstractProcessor<K, V> {
+    private class KStreamWindowAggregateProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, V> {
         private TimestampedWindowStore<K, Agg> windowStore;
         private TimestampedTupleForwarder<Windowed<K>, Agg> tupleForwarder;
         private Sensor lateRecordDropSensor;
@@ -81,7 +79,7 @@ private class KStreamWindowAggregateProcessor extends AbstractProcessor<K, V> {
         private long observedStreamTime = ConsumerRecord.NO_TIMESTAMP;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             final InternalProcessorContext internalProcessorContext = (InternalProcessorContext) context;
             final StreamsMetricsImpl metrics = internalProcessorContext.metrics();
@@ -194,7 +192,7 @@ private class KStreamWindowAggregateValueGetter implements KTableValueGetter<Win
         private TimestampedWindowStore<K, Agg> windowStore;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             windowStore = context.getStateStore(storeName);
         }
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableAggregate.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableAggregate.java
index 1e6474627d6ff..3ff4dfa78fd0d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableAggregate.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableAggregate.java
@@ -19,14 +19,12 @@
 import org.apache.kafka.streams.errors.StreamsException;
 import org.apache.kafka.streams.kstream.Aggregator;
 import org.apache.kafka.streams.kstream.Initializer;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.state.TimestampedKeyValueStore;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
 
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableAggregate<K, V, T> implements KTableProcessorSupplier<K, V, T> {
 
     private final String storeName;
@@ -54,17 +52,17 @@ public boolean enableSendingOldValues(final boolean forceMaterialization) {
     }
 
     @Override
-    public Processor<K, Change<V>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V>> get() {
         return new KTableAggregateProcessor();
     }
 
-    private class KTableAggregateProcessor extends AbstractProcessor<K, Change<V>> {
+    private class KTableAggregateProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V>> {
         private TimestampedKeyValueStore<K, T> store;
         private TimestampedTupleForwarder<K, T> tupleForwarder;
 
         @SuppressWarnings("unchecked")
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             store = (TimestampedKeyValueStore<K, T>) context.getStateStore(storeName);
             tupleForwarder = new TimestampedTupleForwarder<>(
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
index faee7af4ce401..5eaf2a6daa958 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
@@ -58,7 +58,6 @@
 import org.apache.kafka.streams.kstream.internals.suppress.KTableSuppressProcessorSupplier;
 import org.apache.kafka.streams.kstream.internals.suppress.NamedSuppressed;
 import org.apache.kafka.streams.kstream.internals.suppress.SuppressedInternal;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.processor.internals.InternalTopicProperties;
 import org.apache.kafka.streams.processor.internals.StaticTopicNameExtractor;
 import org.apache.kafka.streams.state.KeyValueStore;
@@ -133,12 +132,13 @@ public class KTableImpl<K, S, V> extends AbstractStream<K, V> implements KTable<
 
     private boolean sendOldValues = false;
 
+    @SuppressWarnings("deprecation") // Old PAPI compatibility.
     public KTableImpl(final String name,
                       final Serde<K> keySerde,
                       final Serde<V> valueSerde,
                       final Set<String> subTopologySourceNodes,
                       final String queryableStoreName,
-                      final ProcessorSupplier<?, ?> processorSupplier,
+                      final org.apache.kafka.streams.processor.ProcessorSupplier<?, ?> processorSupplier,
                       final GraphNode graphNode,
                       final InternalStreamsBuilder builder) {
         super(name, keySerde, valueSerde, subTopologySourceNodes, graphNode, builder);
@@ -542,7 +542,8 @@ public KTable<K, V> suppress(final Suppressed<? super K> suppressed) {
         final String storeName =
             suppressedInternal.name() != null ? suppressedInternal.name() + "-store" : builder.newStoreName(SUPPRESS_NAME);
 
-        final ProcessorSupplier<K, Change<V>> suppressionSupplier = new KTableSuppressProcessorSupplier<>(
+        @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+        final org.apache.kafka.streams.processor.ProcessorSupplier<K, Change<V>> suppressionSupplier = new KTableSuppressProcessorSupplier<>(
             suppressedInternal,
             storeName,
             this
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableInnerJoin.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableInnerJoin.java
index 4626c365dea6c..e448aefaf159b 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableInnerJoin.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableInnerJoin.java
@@ -19,9 +19,6 @@
 import org.apache.kafka.common.metrics.Sensor;
 import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.ValueJoiner;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.To;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
@@ -31,6 +28,7 @@
 import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 class KTableKTableInnerJoin<K, R, V1, V2> extends KTableKTableAbstractJoin<K, R, V1, V2> {
     private static final Logger LOG = LoggerFactory.getLogger(KTableKTableInnerJoin.class);
 
@@ -43,7 +41,7 @@ class KTableKTableInnerJoin<K, R, V1, V2> extends KTableKTableAbstractJoin<K, R,
     }
 
     @Override
-    public Processor<K, Change<V1>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V1>> get() {
         return new KTableKTableJoinProcessor(valueGetterSupplier2.get());
     }
 
@@ -64,7 +62,7 @@ public KTableValueGetter<K, R> get() {
         }
     }
 
-    private class KTableKTableJoinProcessor extends AbstractProcessor<K, Change<V1>> {
+    private class KTableKTableJoinProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V1>> {
 
         private final KTableValueGetter<K, V2> valueGetter;
         private Sensor droppedRecordsSensor;
@@ -74,7 +72,7 @@ private class KTableKTableJoinProcessor extends AbstractProcessor<K, Change<V1>>
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             droppedRecordsSensor = droppedRecordsSensor(
                 Thread.currentThread().getName(),
@@ -137,7 +135,7 @@ private class KTableKTableInnerJoinValueGetter implements KTableValueGetter<K, R
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             valueGetter1.init(context);
             valueGetter2.init(context);
         }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableJoinMerger.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableJoinMerger.java
index 3ca0160d24220..36c94b546bf21 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableJoinMerger.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableJoinMerger.java
@@ -16,9 +16,6 @@
  */
 package org.apache.kafka.streams.kstream.internals;
 
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.state.TimestampedKeyValueStore;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
 
@@ -26,6 +23,7 @@
 import java.util.HashSet;
 import java.util.Set;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableKTableJoinMerger<K, V> implements KTableProcessorSupplier<K, V, V> {
 
     private final KTableProcessorSupplier<K, ?, V> parent1;
@@ -46,7 +44,7 @@ public String getQueryableName() {
     }
 
     @Override
-    public Processor<K, Change<V>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V>> get() {
         return new KTableKTableJoinMergeProcessor();
     }
 
@@ -96,13 +94,13 @@ public static <K, V> KTableKTableJoinMerger<K, V> of(final KTableProcessorSuppli
         return new KTableKTableJoinMerger<>(parent1, parent2, queryableName);
     }
 
-    private class KTableKTableJoinMergeProcessor extends AbstractProcessor<K, Change<V>> {
+    private class KTableKTableJoinMergeProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V>> {
         private TimestampedKeyValueStore<K, V> store;
         private TimestampedTupleForwarder<K, V> tupleForwarder;
 
         @SuppressWarnings("unchecked")
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             if (queryableName != null) {
                 store = (TimestampedKeyValueStore<K, V>) context.getStateStore(queryableName);
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableLeftJoin.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableLeftJoin.java
index abc28c0a477b3..dc274cdae0223 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableLeftJoin.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableLeftJoin.java
@@ -18,9 +18,6 @@
 
 import org.apache.kafka.common.metrics.Sensor;
 import org.apache.kafka.streams.kstream.ValueJoiner;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.To;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
@@ -31,6 +28,7 @@
 import static org.apache.kafka.streams.processor.internals.RecordQueue.UNKNOWN;
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 class KTableKTableLeftJoin<K, R, V1, V2> extends KTableKTableAbstractJoin<K, R, V1, V2> {
     private static final Logger LOG = LoggerFactory.getLogger(KTableKTableLeftJoin.class);
 
@@ -41,7 +39,7 @@ class KTableKTableLeftJoin<K, R, V1, V2> extends KTableKTableAbstractJoin<K, R,
     }
 
     @Override
-    public Processor<K, Change<V1>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V1>> get() {
         return new KTableKTableLeftJoinProcessor(valueGetterSupplier2.get());
     }
 
@@ -63,7 +61,7 @@ public KTableValueGetter<K, R> get() {
     }
 
 
-    private class KTableKTableLeftJoinProcessor extends AbstractProcessor<K, Change<V1>> {
+    private class KTableKTableLeftJoinProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V1>> {
 
         private final KTableValueGetter<K, V2> valueGetter;
         private Sensor droppedRecordsSensor;
@@ -73,7 +71,7 @@ private class KTableKTableLeftJoinProcessor extends AbstractProcessor<K, Change<
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             droppedRecordsSensor = droppedRecordsSensor(
                 Thread.currentThread().getName(),
@@ -143,7 +141,7 @@ private class KTableKTableLeftJoinValueGetter implements KTableValueGetter<K, R>
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             valueGetter1.init(context);
             valueGetter2.init(context);
         }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableOuterJoin.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableOuterJoin.java
index 4eaee6b475820..6b2017a439655 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableOuterJoin.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableOuterJoin.java
@@ -18,9 +18,6 @@
 
 import org.apache.kafka.common.metrics.Sensor;
 import org.apache.kafka.streams.kstream.ValueJoiner;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.To;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
@@ -31,6 +28,7 @@
 import static org.apache.kafka.streams.processor.internals.RecordQueue.UNKNOWN;
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 class KTableKTableOuterJoin<K, R, V1, V2> extends KTableKTableAbstractJoin<K, R, V1, V2> {
     private static final Logger LOG = LoggerFactory.getLogger(KTableKTableOuterJoin.class);
 
@@ -41,7 +39,7 @@ class KTableKTableOuterJoin<K, R, V1, V2> extends KTableKTableAbstractJoin<K, R,
     }
 
     @Override
-    public Processor<K, Change<V1>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V1>> get() {
         return new KTableKTableOuterJoinProcessor(valueGetterSupplier2.get());
     }
 
@@ -62,7 +60,7 @@ public KTableValueGetter<K, R> get() {
         }
     }
 
-    private class KTableKTableOuterJoinProcessor extends AbstractProcessor<K, Change<V1>> {
+    private class KTableKTableOuterJoinProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V1>> {
 
         private final KTableValueGetter<K, V2> valueGetter;
         private Sensor droppedRecordsSensor;
@@ -72,7 +70,7 @@ private class KTableKTableOuterJoinProcessor extends AbstractProcessor<K, Change
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             droppedRecordsSensor = droppedRecordsSensor(
                 Thread.currentThread().getName(),
@@ -138,7 +136,7 @@ private class KTableKTableOuterJoinValueGetter implements KTableValueGetter<K, R
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             valueGetter1.init(context);
             valueGetter2.init(context);
         }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableRightJoin.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableRightJoin.java
index 36b16b0a115a2..f948cfe29e487 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableRightJoin.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableKTableRightJoin.java
@@ -18,9 +18,6 @@
 
 import org.apache.kafka.common.metrics.Sensor;
 import org.apache.kafka.streams.kstream.ValueJoiner;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.To;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
@@ -30,6 +27,7 @@
 import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 class KTableKTableRightJoin<K, R, V1, V2> extends KTableKTableAbstractJoin<K, R, V1, V2> {
     private static final Logger LOG = LoggerFactory.getLogger(KTableKTableRightJoin.class);
 
@@ -40,7 +38,7 @@ class KTableKTableRightJoin<K, R, V1, V2> extends KTableKTableAbstractJoin<K, R,
     }
 
     @Override
-    public Processor<K, Change<V1>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V1>> get() {
         return new KTableKTableRightJoinProcessor(valueGetterSupplier2.get());
     }
 
@@ -61,7 +59,7 @@ public KTableValueGetter<K, R> get() {
         }
     }
 
-    private class KTableKTableRightJoinProcessor extends AbstractProcessor<K, Change<V1>> {
+    private class KTableKTableRightJoinProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V1>> {
 
         private final KTableValueGetter<K, V2> valueGetter;
         private Sensor droppedRecordsSensor;
@@ -71,7 +69,7 @@ private class KTableKTableRightJoinProcessor extends AbstractProcessor<K, Change
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             droppedRecordsSensor = droppedRecordsSensor(
                 Thread.currentThread().getName(),
@@ -134,7 +132,7 @@ private class KTableKTableRightJoinValueGetter implements KTableValueGetter<K, R
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             valueGetter1.init(context);
             valueGetter2.init(context);
         }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableMapValues.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableMapValues.java
index 9905cd13985b6..be6d181f4554f 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableMapValues.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableMapValues.java
@@ -17,15 +17,13 @@
 package org.apache.kafka.streams.kstream.internals;
 
 import org.apache.kafka.streams.kstream.ValueMapperWithKey;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.state.TimestampedKeyValueStore;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
 
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 class KTableMapValues<K, V, V1> implements KTableProcessorSupplier<K, V, V1> {
     private final KTableImpl<K, ?, V> parent;
     private final ValueMapperWithKey<? super K, ? super V, ? extends V1> mapper;
@@ -41,7 +39,7 @@ class KTableMapValues<K, V, V1> implements KTableProcessorSupplier<K, V, V1> {
     }
 
     @Override
-    public Processor<K, Change<V>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V>> get() {
         return new KTableMapValuesProcessor();
     }
 
@@ -104,12 +102,12 @@ private ValueAndTimestamp<V1> computeValueAndTimestamp(final K key, final ValueA
     }
 
 
-    private class KTableMapValuesProcessor extends AbstractProcessor<K, Change<V>> {
+    private class KTableMapValuesProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V>> {
         private TimestampedKeyValueStore<K, V1> store;
         private TimestampedTupleForwarder<K, V1> tupleForwarder;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             if (queryableName != null) {
                 store = context.getStateStore(queryableName);
@@ -154,7 +152,7 @@ private class KTableMapValuesValueGetter implements KTableValueGetter<K, V1> {
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             parentGetter.init(context);
         }
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTablePassThrough.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTablePassThrough.java
index 2f16d0e3c064d..8a4947969bdcb 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTablePassThrough.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTablePassThrough.java
@@ -16,14 +16,12 @@
  */
 package org.apache.kafka.streams.kstream.internals;
 
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.state.TimestampedKeyValueStore;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
 
 import java.util.Collection;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTablePassThrough<K, V> implements KTableProcessorSupplier<K, V, V> {
     private final Collection<KStreamAggProcessorSupplier> parents;
     private final String storeName;
@@ -35,7 +33,7 @@ public class KTablePassThrough<K, V> implements KTableProcessorSupplier<K, V, V>
     }
 
     @Override
-    public Processor<K, Change<V>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V>> get() {
         return new KTablePassThroughProcessor();
     }
 
@@ -64,7 +62,7 @@ public String[] storeNames() {
         };
     }
 
-    private class KTablePassThroughProcessor extends AbstractProcessor<K, Change<V>> {
+    private class KTablePassThroughProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V>> {
         @Override
         public void process(final K key, final Change<V> value) {
             context().forward(key, value);
@@ -75,7 +73,7 @@ private class KTablePassThroughValueGetter implements KTableValueGetter<K, V> {
         private TimestampedKeyValueStore<K, V> store;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             store = context.getStateStore(storeName);
         }
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableProcessorSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableProcessorSupplier.java
index ff6f9d61df969..6f30dbb476340 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableProcessorSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableProcessorSupplier.java
@@ -16,9 +16,8 @@
  */
 package org.apache.kafka.streams.kstream.internals;
 
-import org.apache.kafka.streams.processor.ProcessorSupplier;
-
-public interface KTableProcessorSupplier<K, V, T> extends ProcessorSupplier<K, Change<V>> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public interface KTableProcessorSupplier<K, V, T> extends org.apache.kafka.streams.processor.ProcessorSupplier<K, Change<V>> {
 
     KTableValueGetterSupplier<K, T> view();
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableReduce.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableReduce.java
index 88f62f96d5d6b..72f75ea25ded4 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableReduce.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableReduce.java
@@ -18,14 +18,12 @@
 
 import org.apache.kafka.streams.errors.StreamsException;
 import org.apache.kafka.streams.kstream.Reducer;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.state.TimestampedKeyValueStore;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
 
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableReduce<K, V> implements KTableProcessorSupplier<K, V, V> {
 
     private final String storeName;
@@ -48,18 +46,18 @@ public boolean enableSendingOldValues(final boolean forceMaterialization) {
     }
 
     @Override
-    public Processor<K, Change<V>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V>> get() {
         return new KTableReduceProcessor();
     }
 
-    private class KTableReduceProcessor extends AbstractProcessor<K, Change<V>> {
+    private class KTableReduceProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V>> {
 
         private TimestampedKeyValueStore<K, V> store;
         private TimestampedTupleForwarder<K, V> tupleForwarder;
 
         @SuppressWarnings("unchecked")
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             store = (TimestampedKeyValueStore<K, V>) context.getStateStore(storeName);
             tupleForwarder = new TimestampedTupleForwarder<>(
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableRepartitionMap.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableRepartitionMap.java
index d5dc5db0f44d8..6df6ce5ff95e6 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableRepartitionMap.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableRepartitionMap.java
@@ -19,9 +19,6 @@
 import org.apache.kafka.streams.KeyValue;
 import org.apache.kafka.streams.errors.StreamsException;
 import org.apache.kafka.streams.kstream.KeyValueMapper;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
 
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
@@ -31,6 +28,7 @@
  * <p>
  * Given the input, it can output at most two records (one mapped from old value and one mapped from new value).
  */
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableRepartitionMap<K, V, K1, V1> implements KTableProcessorSupplier<K, V, KeyValue<K1, V1>> {
 
     private final KTableImpl<K, ?, V> parent;
@@ -42,7 +40,7 @@ public class KTableRepartitionMap<K, V, K1, V1> implements KTableProcessorSuppli
     }
 
     @Override
-    public Processor<K, Change<V>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V>> get() {
         return new KTableMapProcessor();
     }
 
@@ -72,7 +70,7 @@ public boolean enableSendingOldValues(final boolean forceMaterialization) {
         throw new IllegalStateException("KTableRepartitionMap should always require sending old values.");
     }
 
-    private class KTableMapProcessor extends AbstractProcessor<K, Change<V>> {
+    private class KTableMapProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V>> {
 
         /**
          * @throws StreamsException if key is null
@@ -103,14 +101,14 @@ public void process(final K key, final Change<V> change) {
 
     private class KTableMapValueGetter implements KTableValueGetter<K, KeyValue<K1, V1>> {
         private final KTableValueGetter<K, V> parentGetter;
-        private ProcessorContext context;
+        private org.apache.kafka.streams.processor.ProcessorContext context;
 
         KTableMapValueGetter(final KTableValueGetter<K, V> parentGetter) {
             this.parentGetter = parentGetter;
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             this.context = context;
             parentGetter.init(context);
         }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableSource.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableSource.java
index 1e8835d8d9897..04dbd95498a4c 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableSource.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableSource.java
@@ -17,10 +17,6 @@
 package org.apache.kafka.streams.kstream.internals;
 
 import org.apache.kafka.common.metrics.Sensor;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.state.TimestampedKeyValueStore;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
@@ -31,7 +27,8 @@
 
 import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
 
-public class KTableSource<K, V> implements ProcessorSupplier<K, V> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public class KTableSource<K, V> implements org.apache.kafka.streams.processor.ProcessorSupplier<K, V> {
     private static final Logger LOG = LoggerFactory.getLogger(KTableSource.class);
 
     private final String storeName;
@@ -51,7 +48,7 @@ public String queryableName() {
     }
 
     @Override
-    public Processor<K, V> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V> get() {
         return new KTableSourceProcessor();
     }
 
@@ -72,7 +69,7 @@ public boolean materialized() {
         return queryableName != null;
     }
 
-    private class KTableSourceProcessor extends AbstractProcessor<K, V> {
+    private class KTableSourceProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, V> {
 
         private TimestampedKeyValueStore<K, V> store;
         private TimestampedTupleForwarder<K, V> tupleForwarder;
@@ -80,7 +77,7 @@ private class KTableSourceProcessor extends AbstractProcessor<K, V> {
 
         @SuppressWarnings("unchecked")
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             final StreamsMetricsImpl metrics = (StreamsMetricsImpl) context.metrics();
             droppedRecordsSensor = droppedRecordsSensor(Thread.currentThread().getName(), context.taskId().toString(), metrics);
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableTransformValues.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableTransformValues.java
index f45d32c613da6..94a1c0e629290 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableTransformValues.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableTransformValues.java
@@ -19,9 +19,6 @@
 import org.apache.kafka.common.header.internals.RecordHeaders;
 import org.apache.kafka.streams.kstream.ValueTransformerWithKey;
 import org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.ForwardingDisabledProcessorContext;
 import org.apache.kafka.streams.processor.internals.InternalProcessorContext;
 import org.apache.kafka.streams.processor.internals.ProcessorRecordContext;
@@ -33,6 +30,7 @@
 import static org.apache.kafka.streams.processor.internals.RecordQueue.UNKNOWN;
 import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 class KTableTransformValues<K, V, V1> implements KTableProcessorSupplier<K, V, V1> {
     private final KTableImpl<K, ?, V> parent;
     private final ValueTransformerWithKeySupplier<? super K, ? super V, ? extends V1> transformerSupplier;
@@ -48,7 +46,7 @@ class KTableTransformValues<K, V, V1> implements KTableProcessorSupplier<K, V, V
     }
 
     @Override
-    public Processor<K, Change<V>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V>> get() {
         return new KTableTransformValuesProcessor(transformerSupplier.get());
     }
 
@@ -87,7 +85,7 @@ public boolean enableSendingOldValues(final boolean forceMaterialization) {
         return sendOldValues;
     }
 
-    private class KTableTransformValuesProcessor extends AbstractProcessor<K, Change<V>> {
+    private class KTableTransformValuesProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V>> {
         private final ValueTransformerWithKey<? super K, ? super V, ? extends V1> valueTransformer;
         private TimestampedKeyValueStore<K, V1> store;
         private TimestampedTupleForwarder<K, V1> tupleForwarder;
@@ -97,7 +95,7 @@ private KTableTransformValuesProcessor(final ValueTransformerWithKey<? super K,
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             valueTransformer.init(new ForwardingDisabledProcessorContext(context));
             if (queryableName != null) {
@@ -143,7 +141,7 @@ private class KTableTransformValuesGetter implements KTableValueGetter<K, V1> {
         }
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             internalProcessorContext = (InternalProcessorContext) context;
             parentGetter.init(context);
             valueTransformer.init(new ForwardingDisabledProcessorContext(context));
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/ForeignJoinSubscriptionProcessorSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/ForeignJoinSubscriptionProcessorSupplier.java
index 086c83022add6..7b1ec66bf6dfb 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/ForeignJoinSubscriptionProcessorSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/ForeignJoinSubscriptionProcessorSupplier.java
@@ -22,10 +22,6 @@
 import org.apache.kafka.streams.KeyValue;
 import org.apache.kafka.streams.errors.StreamsException;
 import org.apache.kafka.streams.kstream.internals.Change;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.processor.internals.InternalProcessorContext;
 import org.apache.kafka.streams.processor.internals.metrics.TaskMetrics;
 import org.apache.kafka.streams.state.KeyValueIterator;
@@ -37,7 +33,8 @@
 
 import java.nio.ByteBuffer;
 
-public class ForeignJoinSubscriptionProcessorSupplier<K, KO, VO> implements ProcessorSupplier<KO, Change<VO>> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public class ForeignJoinSubscriptionProcessorSupplier<K, KO, VO> implements org.apache.kafka.streams.processor.ProcessorSupplier<KO, Change<VO>> {
     private static final Logger LOG = LoggerFactory.getLogger(ForeignJoinSubscriptionProcessorSupplier.class);
     private final StoreBuilder<TimestampedKeyValueStore<Bytes, SubscriptionWrapper<K>>> storeBuilder;
     private final CombinedKeySchema<KO, K> keySchema;
@@ -51,17 +48,17 @@ public ForeignJoinSubscriptionProcessorSupplier(
     }
 
     @Override
-    public Processor<KO, Change<VO>> get() {
+    public org.apache.kafka.streams.processor.Processor<KO, Change<VO>> get() {
         return new KTableKTableJoinProcessor();
     }
 
 
-    private final class KTableKTableJoinProcessor extends AbstractProcessor<KO, Change<VO>> {
+    private final class KTableKTableJoinProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<KO, Change<VO>> {
         private Sensor droppedRecordsSensor;
         private TimestampedKeyValueStore<Bytes, SubscriptionWrapper<K>> store;
 
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             final InternalProcessorContext<?, ?> internalProcessorContext = (InternalProcessorContext<?, ?>) context;
             droppedRecordsSensor = TaskMetrics.droppedRecordsSensor(
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/ForeignJoinSubscriptionSendProcessorSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/ForeignJoinSubscriptionSendProcessorSupplier.java
index 4e19b4f64b2aa..8f1e1f9e65495 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/ForeignJoinSubscriptionSendProcessorSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/ForeignJoinSubscriptionSendProcessorSupplier.java
@@ -21,10 +21,6 @@
 import org.apache.kafka.common.serialization.Serde;
 import org.apache.kafka.common.serialization.Serializer;
 import org.apache.kafka.streams.kstream.internals.Change;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
 import org.apache.kafka.streams.processor.internals.metrics.TaskMetrics;
 import org.apache.kafka.streams.state.internals.Murmur3;
@@ -40,7 +36,8 @@
 import static org.apache.kafka.streams.kstream.internals.foreignkeyjoin.SubscriptionWrapper.Instruction.PROPAGATE_NULL_IF_NO_FK_VAL_AVAILABLE;
 import static org.apache.kafka.streams.kstream.internals.foreignkeyjoin.SubscriptionWrapper.Instruction.PROPAGATE_ONLY_IF_FK_VAL_AVAILABLE;
 
-public class ForeignJoinSubscriptionSendProcessorSupplier<K, KO, V> implements ProcessorSupplier<K, Change<V>> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public class ForeignJoinSubscriptionSendProcessorSupplier<K, KO, V> implements org.apache.kafka.streams.processor.ProcessorSupplier<K, Change<V>> {
     private static final Logger LOG = LoggerFactory.getLogger(ForeignJoinSubscriptionSendProcessorSupplier.class);
 
     private final Function<V, KO> foreignKeyExtractor;
@@ -65,11 +62,11 @@ public ForeignJoinSubscriptionSendProcessorSupplier(final Function<V, KO> foreig
     }
 
     @Override
-    public Processor<K, Change<V>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V>> get() {
         return new UnbindChangeProcessor();
     }
 
-    private class UnbindChangeProcessor extends AbstractProcessor<K, Change<V>> {
+    private class UnbindChangeProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V>> {
 
         private Sensor droppedRecordsSensor;
         private String foreignKeySerdeTopic;
@@ -77,7 +74,7 @@ private class UnbindChangeProcessor extends AbstractProcessor<K, Change<V>> {
 
         @SuppressWarnings("unchecked")
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             foreignKeySerdeTopic = foreignKeySerdeTopicSupplier.get();
             valueSerdeTopic = valueSerdeTopicSupplier.get();
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionJoinForeignProcessorSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionJoinForeignProcessorSupplier.java
index 2544eb1856b7c..7c53a6881f21f 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionJoinForeignProcessorSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionJoinForeignProcessorSupplier.java
@@ -21,10 +21,6 @@
 import org.apache.kafka.streams.kstream.internals.Change;
 import org.apache.kafka.streams.kstream.internals.KTableValueGetter;
 import org.apache.kafka.streams.kstream.internals.KTableValueGetterSupplier;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.processor.To;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
 
@@ -39,8 +35,9 @@
  * @param <KO> Type of foreign key
  * @param <VO> Type of foreign value
  */
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class SubscriptionJoinForeignProcessorSupplier<K, KO, VO>
-    implements ProcessorSupplier<CombinedKey<KO, K>, Change<ValueAndTimestamp<SubscriptionWrapper<K>>>> {
+    implements org.apache.kafka.streams.processor.ProcessorSupplier<CombinedKey<KO, K>, Change<ValueAndTimestamp<SubscriptionWrapper<K>>>> {
 
     private final KTableValueGetterSupplier<KO, VO> foreignValueGetterSupplier;
 
@@ -49,14 +46,14 @@ public SubscriptionJoinForeignProcessorSupplier(final KTableValueGetterSupplier<
     }
 
     @Override
-    public Processor<CombinedKey<KO, K>, Change<ValueAndTimestamp<SubscriptionWrapper<K>>>> get() {
+    public org.apache.kafka.streams.processor.Processor<CombinedKey<KO, K>, Change<ValueAndTimestamp<SubscriptionWrapper<K>>>> get() {
 
-        return new AbstractProcessor<CombinedKey<KO, K>, Change<ValueAndTimestamp<SubscriptionWrapper<K>>>>() {
+        return new org.apache.kafka.streams.processor.AbstractProcessor<CombinedKey<KO, K>, Change<ValueAndTimestamp<SubscriptionWrapper<K>>>>() {
 
             private KTableValueGetter<KO, VO> foreignValues;
 
             @Override
-            public void init(final ProcessorContext context) {
+            public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
                 super.init(context);
                 foreignValues = foreignValueGetterSupplier.get();
                 foreignValues.init(context);
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionResolverJoinProcessorSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionResolverJoinProcessorSupplier.java
index 3cd06368a7131..652adbd102983 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionResolverJoinProcessorSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionResolverJoinProcessorSupplier.java
@@ -22,10 +22,6 @@
 import org.apache.kafka.streams.kstream.ValueJoiner;
 import org.apache.kafka.streams.kstream.internals.KTableValueGetter;
 import org.apache.kafka.streams.kstream.internals.KTableValueGetterSupplier;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
 import org.apache.kafka.streams.state.internals.Murmur3;
 
@@ -41,7 +37,8 @@
  * @param <VO> Type of foreign values
  * @param <VR> Type of joined result of primary and foreign values
  */
-public class SubscriptionResolverJoinProcessorSupplier<K, V, VO, VR> implements ProcessorSupplier<K, SubscriptionResponseWrapper<VO>> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public class SubscriptionResolverJoinProcessorSupplier<K, V, VO, VR> implements org.apache.kafka.streams.processor.ProcessorSupplier<K, SubscriptionResponseWrapper<VO>> {
     private final KTableValueGetterSupplier<K, V> valueGetterSupplier;
     private final Serializer<V> constructionTimeValueSerializer;
     private final Supplier<String> valueHashSerdePseudoTopicSupplier;
@@ -61,8 +58,8 @@ public SubscriptionResolverJoinProcessorSupplier(final KTableValueGetterSupplier
     }
 
     @Override
-    public Processor<K, SubscriptionResponseWrapper<VO>> get() {
-        return new AbstractProcessor<K, SubscriptionResponseWrapper<VO>>() {
+    public org.apache.kafka.streams.processor.Processor<K, SubscriptionResponseWrapper<VO>> get() {
+        return new org.apache.kafka.streams.processor.AbstractProcessor<K, SubscriptionResponseWrapper<VO>>() {
             private String valueHashSerdePseudoTopic;
             private Serializer<V> runtimeValueSerializer = constructionTimeValueSerializer;
 
@@ -70,7 +67,7 @@ public Processor<K, SubscriptionResponseWrapper<VO>> get() {
 
             @SuppressWarnings("unchecked")
             @Override
-            public void init(final ProcessorContext context) {
+            public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
                 super.init(context);
                 valueHashSerdePseudoTopic = valueHashSerdePseudoTopicSupplier.get();
                 valueGetter = valueGetterSupplier.get();
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionStoreReceiveProcessorSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionStoreReceiveProcessorSupplier.java
index 4746fc6e9461f..928bd4831a8cd 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionStoreReceiveProcessorSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionStoreReceiveProcessorSupplier.java
@@ -21,10 +21,6 @@
 import org.apache.kafka.common.metrics.Sensor;
 import org.apache.kafka.common.utils.Bytes;
 import org.apache.kafka.streams.kstream.internals.Change;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.processor.To;
 import org.apache.kafka.streams.processor.internals.InternalProcessorContext;
 import org.apache.kafka.streams.processor.internals.metrics.TaskMetrics;
@@ -34,8 +30,9 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class SubscriptionStoreReceiveProcessorSupplier<K, KO>
-    implements ProcessorSupplier<KO, SubscriptionWrapper<K>> {
+    implements org.apache.kafka.streams.processor.ProcessorSupplier<KO, SubscriptionWrapper<K>> {
     private static final Logger LOG = LoggerFactory.getLogger(SubscriptionStoreReceiveProcessorSupplier.class);
 
     private final StoreBuilder<TimestampedKeyValueStore<Bytes, SubscriptionWrapper<K>>> storeBuilder;
@@ -50,15 +47,15 @@ public SubscriptionStoreReceiveProcessorSupplier(
     }
 
     @Override
-    public Processor<KO, SubscriptionWrapper<K>> get() {
+    public org.apache.kafka.streams.processor.Processor<KO, SubscriptionWrapper<K>> get() {
 
-        return new AbstractProcessor<KO, SubscriptionWrapper<K>>() {
+        return new org.apache.kafka.streams.processor.AbstractProcessor<KO, SubscriptionWrapper<K>>() {
 
             private TimestampedKeyValueStore<Bytes, SubscriptionWrapper<K>> store;
             private Sensor droppedRecordsSensor;
 
             @Override
-            public void init(final ProcessorContext context) {
+            public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
                 super.init(context);
                 final InternalProcessorContext<?, ?> internalProcessorContext = (InternalProcessorContext<?, ?>) context;
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/GraphGraceSearchUtil.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/GraphGraceSearchUtil.java
index 017087e6404c8..4b39219a371e5 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/GraphGraceSearchUtil.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/GraphGraceSearchUtil.java
@@ -23,7 +23,6 @@
 import org.apache.kafka.streams.kstream.internals.KStreamSessionWindowAggregate;
 import org.apache.kafka.streams.kstream.internals.KStreamSlidingWindowAggregate;
 import org.apache.kafka.streams.kstream.internals.KStreamWindowAggregate;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 
 public final class GraphGraceSearchUtil {
     private GraphGraceSearchUtil() {}
@@ -72,7 +71,8 @@ private static long findAndVerifyWindowGrace(final GraphNode graphNode, final St
 
     private static Long extractGracePeriod(final GraphNode node) {
         if (node instanceof StatefulProcessorNode) {
-            final ProcessorSupplier processorSupplier = ((StatefulProcessorNode) node).processorParameters().oldProcessorSupplier();
+            @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+            final org.apache.kafka.streams.processor.ProcessorSupplier processorSupplier = ((StatefulProcessorNode) node).processorParameters().oldProcessorSupplier();
             if (processorSupplier instanceof KStreamWindowAggregate) {
                 final KStreamWindowAggregate kStreamWindowAggregate = (KStreamWindowAggregate) processorSupplier;
                 final Windows windows = kStreamWindowAggregate.windows();
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/ProcessorParameters.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/ProcessorParameters.java
index 018d2b7dc7dd3..9e23c5d418b61 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/ProcessorParameters.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/ProcessorParameters.java
@@ -34,10 +34,12 @@ public class ProcessorParameters<KIn, VIn, KOut, VOut> {
 
     // During the transition to KIP-478, we capture arguments passed from the old API to simplify
     // the performance of casts that we still need to perform. This will eventually be removed.
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     private final org.apache.kafka.streams.processor.ProcessorSupplier<KIn, VIn> oldProcessorSupplier;
     private final ProcessorSupplier<KIn, VIn, KOut, VOut> processorSupplier;
     private final String processorName;
 
+    @SuppressWarnings("deprecation") // Old PAPI compatibility.
     public ProcessorParameters(final org.apache.kafka.streams.processor.ProcessorSupplier<KIn, VIn> processorSupplier,
                                final String processorName) {
         oldProcessorSupplier = processorSupplier;
@@ -56,6 +58,7 @@ public ProcessorSupplier<KIn, VIn, KOut, VOut> processorSupplier() {
         return processorSupplier;
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     public org.apache.kafka.streams.processor.ProcessorSupplier<KIn, VIn> oldProcessorSupplier() {
         return oldProcessorSupplier;
     }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/StatefulProcessorNode.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/StatefulProcessorNode.java
index ad6de37f45cbe..88264f91e68f6 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/StatefulProcessorNode.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/graph/StatefulProcessorNode.java
@@ -101,6 +101,7 @@ public void writeToTopology(final InternalTopologyBuilder topologyBuilder, final
         }
 
         // temporary hack until KIP-478 is fully implemented
+        @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
         final org.apache.kafka.streams.processor.ProcessorSupplier<K, V> oldProcessorSupplier =
             processorParameters().oldProcessorSupplier();
         if (oldProcessorSupplier != null && oldProcessorSupplier.stores() != null) {
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorSupplier.java
index 495f6d04ecac5..5a9f4822aec99 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorSupplier.java
@@ -26,9 +26,6 @@
 import org.apache.kafka.streams.kstream.internals.KTableValueGetter;
 import org.apache.kafka.streams.kstream.internals.KTableValueGetterSupplier;
 import org.apache.kafka.streams.kstream.internals.suppress.TimeDefinitions.TimeDefinition;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.InternalProcessorContext;
 import org.apache.kafka.streams.processor.internals.ProcessorRecordContext;
 import org.apache.kafka.streams.processor.internals.metrics.ProcessorNodeMetrics;
@@ -38,6 +35,7 @@
 
 import static java.util.Objects.requireNonNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableSuppressProcessorSupplier<K, V> implements KTableProcessorSupplier<K, V, V> {
     private final SuppressedInternal<K> suppress;
     private final String storeName;
@@ -54,7 +52,7 @@ public KTableSuppressProcessorSupplier(final SuppressedInternal<K> suppress,
     }
 
     @Override
-    public Processor<K, Change<V>> get() {
+    public org.apache.kafka.streams.processor.Processor<K, Change<V>> get() {
         return new KTableSuppressProcessor<>(suppress, storeName);
     }
 
@@ -70,7 +68,7 @@ public KTableValueGetter<K, V> get() {
                     private TimeOrderedKeyValueBuffer<K, V> buffer;
 
                     @Override
-                    public void init(final ProcessorContext context) {
+                    public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
                         parentGetter.init(context);
                         // the main processor is responsible for the buffer's lifecycle
                         buffer = requireNonNull(context.getStateStore(storeName));
@@ -111,7 +109,7 @@ public boolean enableSendingOldValues(final boolean forceMaterialization) {
         return parentKTable.enableSendingOldValues(forceMaterialization);
     }
 
-    private static final class KTableSuppressProcessor<K, V> extends AbstractProcessor<K, Change<V>> {
+    private static final class KTableSuppressProcessor<K, V> extends org.apache.kafka.streams.processor.AbstractProcessor<K, Change<V>> {
         private final long maxRecords;
         private final long maxBytes;
         private final long suppressDurationMillis;
@@ -138,7 +136,7 @@ private KTableSuppressProcessor(final SuppressedInternal<K> suppress, final Stri
 
         @SuppressWarnings("unchecked")
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
             super.init(context);
             internalProcessorContext = (InternalProcessorContext) context;
             suppressionEmitSensor = ProcessorNodeMetrics.suppressionEmitSensor(
diff --git a/streams/src/main/java/org/apache/kafka/streams/processor/AbstractProcessor.java b/streams/src/main/java/org/apache/kafka/streams/processor/AbstractProcessor.java
index c30a273641e4f..52a213d1a9050 100644
--- a/streams/src/main/java/org/apache/kafka/streams/processor/AbstractProcessor.java
+++ b/streams/src/main/java/org/apache/kafka/streams/processor/AbstractProcessor.java
@@ -22,7 +22,10 @@
  *
  * @param <K> the type of keys
  * @param <V> the type of values
+ * @deprecated Since 3.0. Use {@link org.apache.kafka.streams.processor.api.Processor} or
+ *             {@link org.apache.kafka.streams.processor.api.ContextualProcessor} instead.
  */
+@Deprecated
 public abstract class AbstractProcessor<K, V> implements Processor<K, V> {
 
     protected ProcessorContext context;
diff --git a/streams/src/main/java/org/apache/kafka/streams/processor/ConnectedStoreProvider.java b/streams/src/main/java/org/apache/kafka/streams/processor/ConnectedStoreProvider.java
index 84ba1c879cc33..49c029e70b8a4 100644
--- a/streams/src/main/java/org/apache/kafka/streams/processor/ConnectedStoreProvider.java
+++ b/streams/src/main/java/org/apache/kafka/streams/processor/ConnectedStoreProvider.java
@@ -91,8 +91,8 @@
  * }</pre>
  *
  * @see Topology#addProcessor(String, org.apache.kafka.streams.processor.api.ProcessorSupplier, String...)
- * @see KStream#process(ProcessorSupplier, String...)
- * @see KStream#process(ProcessorSupplier, Named, String...)
+ * @see KStream#process(org.apache.kafka.streams.processor.api.ProcessorSupplier, String...)
+ * @see KStream#process(org.apache.kafka.streams.processor.api.ProcessorSupplier, Named, String...)
  * @see KStream#transform(TransformerSupplier, String...)
  * @see KStream#transform(TransformerSupplier, Named, String...)
  * @see KStream#transformValues(ValueTransformerSupplier, String...)
diff --git a/streams/src/main/java/org/apache/kafka/streams/processor/Processor.java b/streams/src/main/java/org/apache/kafka/streams/processor/Processor.java
index 4046f2f116f8e..9d724ec1378d4 100644
--- a/streams/src/main/java/org/apache/kafka/streams/processor/Processor.java
+++ b/streams/src/main/java/org/apache/kafka/streams/processor/Processor.java
@@ -23,7 +23,9 @@
  *
  * @param <K> the type of keys
  * @param <V> the type of values
+ * @deprecated Since 3.0. Use {@link org.apache.kafka.streams.processor.api.Processor} instead.
  */
+@Deprecated
 public interface Processor<K, V> {
 
     /**
diff --git a/streams/src/main/java/org/apache/kafka/streams/processor/ProcessorContext.java b/streams/src/main/java/org/apache/kafka/streams/processor/ProcessorContext.java
index a598e72d8031b..e1d90442c6949 100644
--- a/streams/src/main/java/org/apache/kafka/streams/processor/ProcessorContext.java
+++ b/streams/src/main/java/org/apache/kafka/streams/processor/ProcessorContext.java
@@ -31,6 +31,7 @@
 /**
  * Processor context interface.
  */
+@SuppressWarnings("deprecation") // Not deprecating the old context, since it is used by Transformers. See KAFKA-10603.
 public interface ProcessorContext {
 
     /**
diff --git a/streams/src/main/java/org/apache/kafka/streams/processor/ProcessorSupplier.java b/streams/src/main/java/org/apache/kafka/streams/processor/ProcessorSupplier.java
index a3e5f30c2c464..e53a63a4215f7 100644
--- a/streams/src/main/java/org/apache/kafka/streams/processor/ProcessorSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/processor/ProcessorSupplier.java
@@ -33,7 +33,9 @@
  *
  * @param <K> the type of keys
  * @param <V> the type of values
+ * @deprecated Since 3.0. Use {@link org.apache.kafka.streams.processor.api.ProcessorSupplier} instead.
  */
+@Deprecated
 public interface ProcessorSupplier<K, V> extends ConnectedStoreProvider, Supplier<Processor<K, V>> {
 
     /**
diff --git a/streams/src/main/java/org/apache/kafka/streams/processor/RecordContext.java b/streams/src/main/java/org/apache/kafka/streams/processor/RecordContext.java
index f0b8ff10d3848..9b21df83dd058 100644
--- a/streams/src/main/java/org/apache/kafka/streams/processor/RecordContext.java
+++ b/streams/src/main/java/org/apache/kafka/streams/processor/RecordContext.java
@@ -21,7 +21,7 @@
 
 /**
  * The context associated with the current record being processed by
- * an {@link Processor}
+ * an {@link org.apache.kafka.streams.processor.api.Processor}
  */
 public interface RecordContext {
 
@@ -79,8 +79,10 @@ public interface RecordContext {
      * <p> If it is triggered while processing a record streamed from the source processor,
      * timestamp is defined as the timestamp of the current input record; the timestamp is extracted from
      * {@link org.apache.kafka.clients.consumer.ConsumerRecord ConsumerRecord} by {@link TimestampExtractor}.
-     * Note, that an upstream {@link Processor} might have set a new timestamp by calling
-     * {@link ProcessorContext#forward(Object, Object, To) forward(..., To.all().withTimestamp(...))}.
+     * Note, that an upstream {@link org.apache.kafka.streams.processor.api.Processor}
+     * might have set a new timestamp by calling
+     * {@link org.apache.kafka.streams.processor.api.ProcessorContext#forward(org.apache.kafka.streams.processor.api.Record)
+     * forward(..., To.all().withTimestamp(...))}.
      * In particular, some Kafka Streams DSL operators set result record timestamps explicitly,
      * to guarantee deterministic results.
      *
diff --git a/streams/src/main/java/org/apache/kafka/streams/processor/internals/InternalTopologyBuilder.java b/streams/src/main/java/org/apache/kafka/streams/processor/internals/InternalTopologyBuilder.java
index 103fc7cae3b49..9b392640570bc 100644
--- a/streams/src/main/java/org/apache/kafka/streams/processor/internals/InternalTopologyBuilder.java
+++ b/streams/src/main/java/org/apache/kafka/streams/processor/internals/InternalTopologyBuilder.java
@@ -217,6 +217,7 @@ private static class ProcessorNodeFactory<KIn, VIn, KOut, VOut> extends NodeFact
             this.supplier = supplier;
         }
 
+        @SuppressWarnings("deprecation") // Old PAPI compatibility.
         ProcessorNodeFactory(final String name,
                              final String[] predecessors,
                              final org.apache.kafka.streams.processor.ProcessorSupplier<KIn, VIn> supplier) {
diff --git a/streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorAdapter.java b/streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorAdapter.java
index f067bbda6472d..f48bfd4b17958 100644
--- a/streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorAdapter.java
+++ b/streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorAdapter.java
@@ -21,6 +21,7 @@
 import org.apache.kafka.streams.processor.api.ProcessorContext;
 import org.apache.kafka.streams.processor.api.Record;
 
+@SuppressWarnings("deprecation") // Old PAPI compatibility
 public final class ProcessorAdapter<KIn, VIn, KOut, VOut> implements Processor<KIn, VIn, KOut, VOut> {
     private final org.apache.kafka.streams.processor.Processor<KIn, VIn> delegate;
     private InternalProcessorContext context;
diff --git a/streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorNode.java b/streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorNode.java
index 9bf35d4f16718..dfc0b70b3511c 100644
--- a/streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorNode.java
+++ b/streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorNode.java
@@ -62,7 +62,7 @@ public ProcessorNode(final String name,
     }
 
     public ProcessorNode(final String name,
-                         final org.apache.kafka.streams.processor.Processor<KIn, VIn> processor,
+                         @SuppressWarnings("deprecation") final org.apache.kafka.streams.processor.Processor<KIn, VIn> processor,
                          final Set<String> stateStores) {
 
         this.name = name;
diff --git a/streams/src/main/java/org/apache/kafka/streams/state/Stores.java b/streams/src/main/java/org/apache/kafka/streams/state/Stores.java
index 12df0e01dffed..bf4e5aaf9ef02 100644
--- a/streams/src/main/java/org/apache/kafka/streams/state/Stores.java
+++ b/streams/src/main/java/org/apache/kafka/streams/state/Stores.java
@@ -57,7 +57,7 @@
  *               .withCachingDisabled());
  * }</pre>
  * When using the Processor API, i.e., {@link org.apache.kafka.streams.Topology Topology}, users create
- * {@link StoreBuilder}s that can be attached to {@link org.apache.kafka.streams.processor.Processor Processor}s.
+ * {@link StoreBuilder}s that can be attached to {@link org.apache.kafka.streams.processor.api.Processor Processor}s.
  * For example, you can create a {@link org.apache.kafka.streams.kstream.Windowed windowed} RocksDB store with custom
  * changelog topic configuration like:
  * <pre>{@code
diff --git a/streams/src/test/java/org/apache/kafka/streams/StreamsBuilderTest.java b/streams/src/test/java/org/apache/kafka/streams/StreamsBuilderTest.java
index 129d29aecfa5c..fba58a1d47d17 100644
--- a/streams/src/test/java/org/apache/kafka/streams/StreamsBuilderTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/StreamsBuilderTest.java
@@ -76,6 +76,7 @@
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class StreamsBuilderTest {
 
     private static final String STREAM_TOPIC = "stream-topic";
diff --git a/streams/src/test/java/org/apache/kafka/streams/integration/GlobalKTableIntegrationTest.java b/streams/src/test/java/org/apache/kafka/streams/integration/GlobalKTableIntegrationTest.java
index 447e0a2e34ac0..4bc69e6fa1446 100644
--- a/streams/src/test/java/org/apache/kafka/streams/integration/GlobalKTableIntegrationTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/integration/GlobalKTableIntegrationTest.java
@@ -66,6 +66,7 @@
 import static org.hamcrest.core.IsEqual.equalTo;
 import static org.junit.Assert.assertNotNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 @Category({IntegrationTest.class})
 public class GlobalKTableIntegrationTest {
     private static final int NUM_BROKERS = 1;
diff --git a/streams/src/test/java/org/apache/kafka/streams/integration/GlobalThreadShutDownOrderTest.java b/streams/src/test/java/org/apache/kafka/streams/integration/GlobalThreadShutDownOrderTest.java
index 5ef4345959dad..6d8932573add4 100644
--- a/streams/src/test/java/org/apache/kafka/streams/integration/GlobalThreadShutDownOrderTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/integration/GlobalThreadShutDownOrderTest.java
@@ -30,7 +30,6 @@
 import org.apache.kafka.streams.integration.utils.EmbeddedKafkaCluster;
 import org.apache.kafka.streams.integration.utils.IntegrationTestUtils;
 import org.apache.kafka.streams.kstream.Consumed;
-import org.apache.kafka.streams.processor.AbstractProcessor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.state.KeyValueStore;
 import org.apache.kafka.streams.state.Stores;
@@ -108,6 +107,7 @@ public static void closeCluster() {
     @Rule
     public TestName testName = new TestName();
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Before
     public void before() throws Exception {
         builder = new StreamsBuilder();
@@ -196,7 +196,8 @@ private void populateTopics(final String topicName) throws Exception {
     }
 
 
-    private class GlobalStoreProcessor extends AbstractProcessor<String, Long> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private class GlobalStoreProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<String, Long> {
 
         private KeyValueStore<String, Long> store;
         private final String storeName;
diff --git a/streams/src/test/java/org/apache/kafka/streams/integration/RestoreIntegrationTest.java b/streams/src/test/java/org/apache/kafka/streams/integration/RestoreIntegrationTest.java
index df0645ed9e2e2..9deb5eb81f622 100644
--- a/streams/src/test/java/org/apache/kafka/streams/integration/RestoreIntegrationTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/integration/RestoreIntegrationTest.java
@@ -40,7 +40,6 @@
 import org.apache.kafka.streams.kstream.Consumed;
 import org.apache.kafka.streams.kstream.KStream;
 import org.apache.kafka.streams.kstream.Materialized;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.StateRestoreListener;
 import org.apache.kafka.streams.processor.TaskId;
@@ -292,6 +291,7 @@ public void shouldSuccessfullyStartWhenLoggingDisabled() throws InterruptedExcep
         assertTrue(startupLatch.await(30, TimeUnit.SECONDS));
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void shouldProcessDataFromStoresWithLoggingDisabled() throws InterruptedException {
 
@@ -430,7 +430,8 @@ static int numStoresClosed() {
         }
     }
 
-    public static class KeyValueStoreProcessor implements Processor<Integer, Integer> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    public static class KeyValueStoreProcessor implements org.apache.kafka.streams.processor.Processor<Integer, Integer> {
 
         private final String topic;
         private final CountDownLatch processorLatch;
diff --git a/streams/src/test/java/org/apache/kafka/streams/integration/StoreUpgradeIntegrationTest.java b/streams/src/test/java/org/apache/kafka/streams/integration/StoreUpgradeIntegrationTest.java
index b332e143346c8..9c6085fec703d 100644
--- a/streams/src/test/java/org/apache/kafka/streams/integration/StoreUpgradeIntegrationTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/integration/StoreUpgradeIntegrationTest.java
@@ -27,7 +27,6 @@
 import org.apache.kafka.streams.integration.utils.IntegrationTestUtils;
 import org.apache.kafka.streams.kstream.Windowed;
 import org.apache.kafka.streams.kstream.internals.TimeWindow;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.state.KeyValueIterator;
 import org.apache.kafka.streams.state.KeyValueStore;
@@ -60,6 +59,7 @@
 import static java.util.Collections.singletonList;
 import static org.apache.kafka.streams.integration.utils.IntegrationTestUtils.safeUniqueTestName;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 @Category({IntegrationTest.class})
 public class StoreUpgradeIntegrationTest {
     private static final String STORE_NAME = "store";
@@ -953,7 +953,8 @@ private <K, V> void processKeyValueAndVerifyWindowedCountWithTimestamp(final K k
             "Could not get expected result in time.");
     }
 
-    private static class KeyValueProcessor implements Processor<Integer, Integer> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private static class KeyValueProcessor implements org.apache.kafka.streams.processor.Processor<Integer, Integer> {
         private KeyValueStore<Integer, Long> store;
 
         @SuppressWarnings("unchecked")
@@ -980,7 +981,8 @@ public void process(final Integer key, final Integer value) {
         public void close() {}
     }
 
-    private static class TimestampedKeyValueProcessor implements Processor<Integer, Integer> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private static class TimestampedKeyValueProcessor implements org.apache.kafka.streams.processor.Processor<Integer, Integer> {
         private ProcessorContext context;
         private TimestampedKeyValueStore<Integer, Long> store;
 
@@ -1013,7 +1015,8 @@ public void process(final Integer key, final Integer value) {
         public void close() {}
     }
 
-    private static class WindowedProcessor implements Processor<Integer, Integer> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private static class WindowedProcessor implements org.apache.kafka.streams.processor.Processor<Integer, Integer> {
         private WindowStore<Integer, Long> store;
 
         @SuppressWarnings("unchecked")
@@ -1040,7 +1043,8 @@ public void process(final Integer key, final Integer value) {
         public void close() {}
     }
 
-    private static class TimestampedWindowedProcessor implements Processor<Integer, Integer> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private static class TimestampedWindowedProcessor implements org.apache.kafka.streams.processor.Processor<Integer, Integer> {
         private ProcessorContext context;
         private TimestampedWindowStore<Integer, Long> store;
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/integration/StreamsUncaughtExceptionHandlerIntegrationTest.java b/streams/src/test/java/org/apache/kafka/streams/integration/StreamsUncaughtExceptionHandlerIntegrationTest.java
index 9288c60443fb0..97d894f03ae29 100644
--- a/streams/src/test/java/org/apache/kafka/streams/integration/StreamsUncaughtExceptionHandlerIntegrationTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/integration/StreamsUncaughtExceptionHandlerIntegrationTest.java
@@ -31,7 +31,6 @@
 import org.apache.kafka.streams.kstream.Consumed;
 import org.apache.kafka.streams.kstream.KStream;
 import org.apache.kafka.streams.kstream.Named;
-import org.apache.kafka.streams.processor.AbstractProcessor;
 import org.apache.kafka.streams.state.Stores;
 import org.apache.kafka.streams.state.internals.KeyValueStoreBuilder;
 import org.apache.kafka.test.IntegrationTest;
@@ -226,7 +225,7 @@ private void produceMessages(final long timestamp, final String streamOneInput,
             timestamp);
     }
 
-    private static class ShutdownProcessor extends AbstractProcessor<String, String> {
+    private static class ShutdownProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<String, String> {
         final List<String> valueList;
 
         ShutdownProcessor(final List<String> valueList) {
diff --git a/streams/src/test/java/org/apache/kafka/streams/integration/TaskMetadataIntegrationTest.java b/streams/src/test/java/org/apache/kafka/streams/integration/TaskMetadataIntegrationTest.java
index b11779211829b..b5edece70c95f 100644
--- a/streams/src/test/java/org/apache/kafka/streams/integration/TaskMetadataIntegrationTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/integration/TaskMetadataIntegrationTest.java
@@ -27,7 +27,6 @@
 import org.apache.kafka.streams.integration.utils.EmbeddedKafkaCluster;
 import org.apache.kafka.streams.integration.utils.IntegrationTestUtils;
 import org.apache.kafka.streams.kstream.KStream;
-import org.apache.kafka.streams.processor.AbstractProcessor;
 import org.apache.kafka.streams.processor.TaskMetadata;
 import org.apache.kafka.test.IntegrationTest;
 import org.apache.kafka.test.TestUtils;
@@ -82,6 +81,7 @@ public static void closeCluster() {
     private AtomicBoolean process;
     private AtomicBoolean commit;
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Before
     public void setup() {
         final String testId = safeUniqueTestName(getClass(), testName);
@@ -180,7 +180,8 @@ private void produceMessages(final long timestamp, final String streamOneInput,
                 timestamp);
     }
 
-    private class PauseProcessor extends AbstractProcessor<String, String> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private class PauseProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<String, String> {
         @Override
         public void process(final String key, final String value) {
             while (!process.get()) {
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/RepartitionTopicNamingTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/RepartitionTopicNamingTest.java
index 3091a6f9e24c8..5545fb6ef1a03 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/RepartitionTopicNamingTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/RepartitionTopicNamingTest.java
@@ -23,7 +23,6 @@
 import org.apache.kafka.streams.StreamsConfig;
 import org.apache.kafka.streams.Topology;
 import org.apache.kafka.streams.errors.TopologyException;
-import org.apache.kafka.streams.processor.AbstractProcessor;
 import org.junit.Test;
 
 import java.time.Duration;
@@ -463,6 +462,7 @@ private int getCountOfRepartitionTopicsFound(final String topologyString, final
     }
 
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     private Topology buildTopology(final String optimizationConfig) {
         final Initializer<Integer> initializer = () -> 0;
         final Aggregator<String, String, Integer> aggregator = (k, v, agg) -> agg + v.length();
@@ -505,7 +505,8 @@ private Topology buildTopology(final String optimizationConfig) {
     }
 
 
-    private static class SimpleProcessor extends AbstractProcessor<String, String> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private static class SimpleProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<String, String> {
 
         final List<String> valueList;
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/AbstractStreamTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/AbstractStreamTest.java
index 4bc7779f5ed6a..067a53129e5fc 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/AbstractStreamTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/AbstractStreamTest.java
@@ -30,9 +30,6 @@
 import org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier;
 import org.apache.kafka.streams.kstream.internals.graph.ProcessorGraphNode;
 import org.apache.kafka.streams.kstream.internals.graph.ProcessorParameters;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.test.MockProcessorSupplier;
 import org.junit.Test;
 
@@ -44,6 +41,7 @@
 import static org.easymock.EasyMock.verify;
 import static org.junit.Assert.assertTrue;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class AbstractStreamTest {
 
     @Test
@@ -71,6 +69,7 @@ public void testToInternalValueTransformerWithKeySupplierSuppliesNewTransformers
         verify(valueTransformerWithKeySupplier);
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testShouldBeExtensible() {
         final StreamsBuilder builder = new StreamsBuilder();
@@ -108,7 +107,7 @@ KStream<K, V> randomFilter() {
         }
     }
 
-    private static class ExtendedKStreamDummy<K, V> implements ProcessorSupplier<K, V> {
+    private static class ExtendedKStreamDummy<K, V> implements org.apache.kafka.streams.processor.ProcessorSupplier<K, V> {
 
         private final Random rand;
 
@@ -117,11 +116,11 @@ private static class ExtendedKStreamDummy<K, V> implements ProcessorSupplier<K,
         }
 
         @Override
-        public Processor<K, V> get() {
+        public org.apache.kafka.streams.processor.Processor<K, V> get() {
             return new ExtendedKStreamDummyProcessor();
         }
 
-        private class ExtendedKStreamDummyProcessor extends AbstractProcessor<K, V> {
+        private class ExtendedKStreamDummyProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<K, V> {
             @Override
             public void process(final K key, final V value) {
                 // flip a coin and filter
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/GlobalKTableJoinsTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/GlobalKTableJoinsTest.java
index a2b8029f4be69..e4d95e0d78e0d 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/GlobalKTableJoinsTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/GlobalKTableJoinsTest.java
@@ -56,6 +56,7 @@ public void setUp() {
         keyValueMapper = (key, value) -> value;
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void shouldLeftJoinWithStream() {
         final MockProcessorSupplier<String, String> supplier = new MockProcessorSupplier<>();
@@ -71,6 +72,7 @@ public void shouldLeftJoinWithStream() {
         verifyJoin(expected, supplier);
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void shouldInnerJoinWithStream() {
         final MockProcessorSupplier<String, String> supplier = new MockProcessorSupplier<>();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KGroupedStreamImplTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KGroupedStreamImplTest.java
index d3b7626c16894..b710e24b64438 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KGroupedStreamImplTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KGroupedStreamImplTest.java
@@ -62,6 +62,7 @@
 import static org.junit.Assert.assertThrows;
 
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KGroupedStreamImplTest {
 
     private static final String TOPIC = "topic";
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KGroupedTableImplTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KGroupedTableImplTest.java
index 130e299ff8835..a870cd3645ee3 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KGroupedTableImplTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KGroupedTableImplTest.java
@@ -126,6 +126,7 @@ public void shouldNotAllowInvalidStoreNameOnReduce() {
             Materialized.as(INVALID_STORE_NAME)));
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     private MockProcessorSupplier<String, Integer> getReducedResults(final KTable<String, Integer> inputKTable) {
         final MockProcessorSupplier<String, Integer> supplier = new MockProcessorSupplier<>();
         inputKTable
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamBranchTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamBranchTest.java
index 1813522bcce2c..8a731f9e47453 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamBranchTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamBranchTest.java
@@ -40,7 +40,7 @@ public class KStreamBranchTest {
     private final String topicName = "topic";
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.String(), Serdes.String());
 
-    @SuppressWarnings({"unchecked", "deprecation"})
+    @SuppressWarnings({"unchecked", "deprecation"}) // Old PAPI. Needs to be migrated.
     @Test
     public void testKStreamBranch() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFilterTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFilterTest.java
index c6c2c7a7c37fb..bc3f46117eafb 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFilterTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFilterTest.java
@@ -40,6 +40,7 @@ public class KStreamFilterTest {
 
     private final Predicate<Integer, String> isMultipleOfThree = (key, value) -> (key % 3) == 0;
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testFilter() {
         final StreamsBuilder builder = new StreamsBuilder();
@@ -61,6 +62,7 @@ public void testFilter() {
         assertEquals(2, supplier.theCapturedProcessor().processed().size());
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testFilterNot() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapTest.java
index e27754a301df8..a792ff668e2c8 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapTest.java
@@ -41,6 +41,7 @@
 public class KStreamFlatMapTest {
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.Integer(), Serdes.String());
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testFlatMap() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapValuesTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapValuesTest.java
index a84fdcc8024eb..c1930e5c885aa 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapValuesTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapValuesTest.java
@@ -41,6 +41,7 @@ public class KStreamFlatMapValuesTest {
     private final String topicName = "topic";
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.Integer(), Serdes.String());
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testFlatMapValues() {
         final StreamsBuilder builder = new StreamsBuilder();
@@ -77,6 +78,7 @@ public void testFlatMapValues() {
     }
 
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testFlatMapValuesWithKeys() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformTest.java
index d18a7a87578da..80822559d11f5 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformTest.java
@@ -20,7 +20,6 @@
 import org.apache.kafka.streams.kstream.Transformer;
 import org.apache.kafka.streams.kstream.TransformerSupplier;
 import org.apache.kafka.streams.kstream.internals.KStreamFlatTransform.KStreamFlatTransformProcessor;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.easymock.EasyMock;
 import org.easymock.EasyMockSupport;
@@ -32,6 +31,7 @@
 
 import static org.junit.Assert.assertTrue;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamFlatTransformTest extends EasyMockSupport {
 
     private Number inputKey;
@@ -129,7 +129,7 @@ public void shouldGetFlatTransformProcessor() {
         EasyMock.expect(transformerSupplier.get()).andReturn(transformer);
         replayAll();
 
-        final Processor<Number, Number> processor = processorSupplier.get();
+        final org.apache.kafka.streams.processor.Processor<Number, Number> processor = processorSupplier.get();
 
         verifyAll();
         assertTrue(processor instanceof KStreamFlatTransformProcessor);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformValuesTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformValuesTest.java
index 36167c04c0ce3..fd6460427ca3e 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformValuesTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatTransformValuesTest.java
@@ -24,7 +24,6 @@
 import org.apache.kafka.streams.kstream.ValueTransformerWithKey;
 import org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier;
 import org.apache.kafka.streams.kstream.internals.KStreamFlatTransformValues.KStreamFlatTransformValuesProcessor;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.ForwardingDisabledProcessorContext;
 import org.easymock.EasyMock;
@@ -32,6 +31,7 @@
 import org.junit.Before;
 import org.junit.Test;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamFlatTransformValuesTest extends EasyMockSupport {
 
     private Integer inputKey;
@@ -127,7 +127,7 @@ public void shouldGetFlatTransformValuesProcessor() {
         EasyMock.expect(valueTransformerSupplier.get()).andReturn(valueTransformer);
         replayAll();
 
-        final Processor<Integer, Integer> processor = processorSupplier.get();
+        final org.apache.kafka.streams.processor.Processor<Integer, Integer> processor = processorSupplier.get();
 
         verifyAll();
         assertTrue(processor instanceof KStreamFlatTransformValuesProcessor);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableJoinTest.java
index abebd52141973..fda87dcff544c 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableJoinTest.java
@@ -55,6 +55,7 @@ public class KStreamGlobalKTableJoinTest {
     private MockProcessor<Integer, String> processor;
     private StreamsBuilder builder;
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Before
     public void setUp() {
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableLeftJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableLeftJoinTest.java
index 2b2541ee4ebb3..9268997ade438 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableLeftJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamGlobalKTableLeftJoinTest.java
@@ -55,6 +55,7 @@ public class KStreamGlobalKTableLeftJoinTest {
     private TopologyTestDriver driver;
     private StreamsBuilder builder;
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Before
     public void setUp() {
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java
index 7bdcea86a4cf5..8464ab960f097 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java
@@ -56,6 +56,7 @@
 import org.apache.kafka.streams.processor.FailOnInvalidTimestamp;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.TopicNameExtractor;
+import org.apache.kafka.streams.processor.api.ProcessorSupplier;
 import org.apache.kafka.streams.processor.internals.ProcessorTopology;
 import org.apache.kafka.streams.processor.internals.SourceNode;
 import org.apache.kafka.streams.state.KeyValueStore;
@@ -99,6 +100,7 @@
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamImplTest {
 
     private final Consumed<String, String> stringConsumed = Consumed.with(Serdes.String(), Serdes.String());
@@ -2381,7 +2383,7 @@ public void shouldNotAllowNullNamedOnFlatTransformValuesWithFlatValueWithKeySupp
     public void shouldNotAllowNullProcessSupplierOnProcess() {
         final NullPointerException exception = assertThrows(
             NullPointerException.class,
-            () -> testStream.process(null));
+            () -> testStream.process((ProcessorSupplier<? super String, ? super String, Void, Void>) null));
         assertThat(exception.getMessage(), equalTo("processorSupplier can't be null"));
     }
 
@@ -2389,7 +2391,8 @@ public void shouldNotAllowNullProcessSupplierOnProcess() {
     public void shouldNotAllowNullProcessSupplierOnProcessWithStores() {
         final NullPointerException exception = assertThrows(
             NullPointerException.class,
-            () -> testStream.process(null, "storeName"));
+            () -> testStream.process((ProcessorSupplier<? super String, ? super String, Void, Void>) null,
+                                     "storeName"));
         assertThat(exception.getMessage(), equalTo("processorSupplier can't be null"));
     }
 
@@ -2397,7 +2400,8 @@ public void shouldNotAllowNullProcessSupplierOnProcessWithStores() {
     public void shouldNotAllowNullProcessSupplierOnProcessWithNamed() {
         final NullPointerException exception = assertThrows(
             NullPointerException.class,
-            () -> testStream.process(null, Named.as("processor")));
+            () -> testStream.process((ProcessorSupplier<? super String, ? super String, Void, Void>) null,
+                                     Named.as("processor")));
         assertThat(exception.getMessage(), equalTo("processorSupplier can't be null"));
     }
 
@@ -2405,7 +2409,8 @@ public void shouldNotAllowNullProcessSupplierOnProcessWithNamed() {
     public void shouldNotAllowNullProcessSupplierOnProcessWithNamedAndStores() {
         final NullPointerException exception = assertThrows(
             NullPointerException.class,
-            () -> testStream.process(null, Named.as("processor"), "stateStore"));
+            () -> testStream.process((ProcessorSupplier<? super String, ? super String, Void, Void>) null,
+                                     Named.as("processor"), "stateStore"));
         assertThat(exception.getMessage(), equalTo("processorSupplier can't be null"));
     }
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoinTest.java
index 00e5b57368a32..7ce9d34b7b850 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoinTest.java
@@ -62,6 +62,7 @@
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamKStreamJoinTest {
     private final static KeyValueTimestamp<?, ?>[] EMPTY = new KeyValueTimestamp[0];
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamLeftJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamLeftJoinTest.java
index d0fb2bed71159..04fdf34a19d48 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamLeftJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamLeftJoinTest.java
@@ -52,6 +52,7 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamKStreamLeftJoinTest {
     private final static KeyValueTimestamp[] EMPTY = new KeyValueTimestamp[0];
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamOuterJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamOuterJoinTest.java
index 9c16c59c16c1d..2b809c7f2d997 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamOuterJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamOuterJoinTest.java
@@ -52,6 +52,7 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamKStreamOuterJoinTest {
     private final String topic1 = "topic1";
     private final String topic2 = "topic2";
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoinTest.java
index c91455d3bda7d..3d338274bea33 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKTableJoinTest.java
@@ -66,6 +66,7 @@ public class KStreamKTableJoinTest {
     private StreamsBuilder builder;
     private final MockProcessorSupplier<Integer, String> supplier = new MockProcessorSupplier<>();
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Before
     public void setUp() {
         builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKTableLeftJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKTableLeftJoinTest.java
index 30e0ff86e11bc..d9f227c1eb32f 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKTableLeftJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamKTableLeftJoinTest.java
@@ -59,6 +59,7 @@ public class KStreamKTableLeftJoinTest {
     private MockProcessor<Integer, String> processor;
     private StreamsBuilder builder;
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Before
     public void setUp() {
         builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapTest.java
index 623dde50c0c9e..60da681df1146 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapTest.java
@@ -39,6 +39,7 @@
 public class KStreamMapTest {
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.Integer(), Serdes.String());
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testMap() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapValuesTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapValuesTest.java
index 057294864babc..fe1e4a3676a20 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapValuesTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapValuesTest.java
@@ -39,6 +39,7 @@ public class KStreamMapValuesTest {
     private final MockProcessorSupplier<Integer, Integer> supplier = new MockProcessorSupplier<>();
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.Integer(), Serdes.String());
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testFlatMapValues() {
         final StreamsBuilder builder = new StreamsBuilder();
@@ -63,6 +64,7 @@ public void testFlatMapValues() {
         assertArrayEquals(expected, supplier.theCapturedProcessor().processed().toArray());
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testMapValuesWithKeys() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSelectKeyTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSelectKeyTest.java
index a7546e900796a..d8e70f90a877b 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSelectKeyTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSelectKeyTest.java
@@ -41,6 +41,7 @@ public class KStreamSelectKeyTest {
     private final String topicName = "topic_key_select";
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.String(), Serdes.Integer());
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testSelectKey() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSessionWindowAggregateProcessorTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSessionWindowAggregateProcessorTest.java
index 94bad59b1e51b..4ab8a45cc2d5a 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSessionWindowAggregateProcessorTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSessionWindowAggregateProcessorTest.java
@@ -33,7 +33,6 @@
 import org.apache.kafka.streams.kstream.Windowed;
 import org.apache.kafka.streams.processor.StateStoreContext;
 import org.apache.kafka.streams.processor.internals.metrics.TaskMetrics;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.To;
 import org.apache.kafka.streams.processor.internals.ProcessorRecordContext;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
@@ -68,6 +67,7 @@
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamSessionWindowAggregateProcessorTest {
 
     private static final long GAP_MS = 5 * 60 * 1000L;
@@ -87,7 +87,7 @@ public class KStreamSessionWindowAggregateProcessorTest {
             sessionMerger);
 
     private final List<KeyValueTimestamp<Windowed<String>, Change<Long>>> results = new ArrayList<>();
-    private final Processor<String, String> processor = sessionAggregator.get();
+    private final org.apache.kafka.streams.processor.Processor<String, String> processor = sessionAggregator.get();
     private SessionStore<String, Long> sessionStore;
     private InternalMockProcessorContext context;
     private final Metrics metrics = new Metrics();
@@ -404,7 +404,7 @@ public void shouldLogAndMeterWhenSkippingNullKeyWithBuiltInMetrics() {
     @Test
     public void shouldLogAndMeterWhenSkippingLateRecordWithZeroGrace() {
         setup(false);
-        final Processor<String, String> processor = new KStreamSessionWindowAggregate<>(
+        final org.apache.kafka.streams.processor.Processor<String, String> processor = new KStreamSessionWindowAggregate<>(
             SessionWindows.with(ofMillis(10L)).grace(ofMillis(0L)),
             STORE_NAME,
             initializer,
@@ -469,7 +469,7 @@ public void shouldLogAndMeterWhenSkippingLateRecordWithZeroGrace() {
     @Test
     public void shouldLogAndMeterWhenSkippingLateRecordWithNonzeroGrace() {
         setup(false);
-        final Processor<String, String> processor = new KStreamSessionWindowAggregate<>(
+        final org.apache.kafka.streams.processor.Processor<String, String> processor = new KStreamSessionWindowAggregate<>(
             SessionWindows.with(ofMillis(10L)).grace(ofMillis(1L)),
             STORE_NAME,
             initializer,
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSlidingWindowAggregateTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSlidingWindowAggregateTest.java
index 0bb2c01226348..65853daeb1776 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSlidingWindowAggregateTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamSlidingWindowAggregateTest.java
@@ -81,6 +81,7 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 @RunWith(Parameterized.class)
 public class KStreamSlidingWindowAggregateTest {
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformTest.java
index 20b1d3a896676..5aad9f07fd133 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformTest.java
@@ -44,6 +44,7 @@ public class KStreamTransformTest {
     private static final String TOPIC_NAME = "topic";
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.Integer(), Serdes.Integer());
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testTransform() {
         final StreamsBuilder builder = new StreamsBuilder();
@@ -106,6 +107,7 @@ public void close() { }
         }
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testTransformWithNewDriverAndPunctuator() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValuesTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValuesTest.java
index 96f80ff93aadc..983e52db5c19f 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValuesTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValuesTest.java
@@ -27,7 +27,6 @@
 import org.apache.kafka.streams.kstream.ValueTransformerSupplier;
 import org.apache.kafka.streams.kstream.ValueTransformerWithKey;
 import org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.ForwardingDisabledProcessorContext;
 import org.apache.kafka.streams.TestInputTopic;
@@ -47,6 +46,7 @@
 import static org.junit.Assert.assertArrayEquals;
 
 @RunWith(EasyMockRunner.class)
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KStreamTransformValuesTest {
     private final String topicName = "topic";
     private final MockProcessorSupplier<Integer, Integer> supplier = new MockProcessorSupplier<>();
@@ -54,6 +54,7 @@ public class KStreamTransformValuesTest {
     @Mock(MockType.NICE)
     private ProcessorContext context;
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testTransform() {
         final StreamsBuilder builder = new StreamsBuilder();
@@ -96,6 +97,7 @@ public void close() { }
         assertArrayEquals(expected, supplier.theCapturedProcessor().processed().toArray());
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testTransformWithKey() {
         final StreamsBuilder builder = new StreamsBuilder();
@@ -143,7 +145,7 @@ public void close() { }
     public void shouldInitializeTransformerWithForwardDisabledProcessorContext() {
         final NoOpValueTransformerWithKeySupplier<String, String> transformer = new NoOpValueTransformerWithKeySupplier<>();
         final KStreamTransformValues<String, String, String> transformValues = new KStreamTransformValues<>(transformer);
-        final Processor<String, String> processor = transformValues.get();
+        final org.apache.kafka.streams.processor.Processor<String, String> processor = transformValues.get();
 
         processor.init(context);
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamWindowAggregateTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamWindowAggregateTest.java
index 88f3091f8a95e..39a74447dacff 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamWindowAggregateTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamWindowAggregateTest.java
@@ -66,6 +66,7 @@ public class KStreamWindowAggregateTest {
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.String(), Serdes.String());
     private final String threadId = Thread.currentThread().getName();
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testAggBasic() {
         final StreamsBuilder builder = new StreamsBuilder();
@@ -143,6 +144,7 @@ public void testAggBasic() {
         );
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testJoin() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableAggregateTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableAggregateTest.java
index b188853d27ecb..a61ed12d3a7b4 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableAggregateTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableAggregateTest.java
@@ -49,6 +49,7 @@
 import static org.apache.kafka.common.utils.Utils.mkProperties;
 import static org.junit.Assert.assertEquals;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableAggregateTest {
     private final Serde<String> stringSerde = Serdes.String();
     private final Consumed<String, String> consumed = Consumed.with(stringSerde, stringSerde);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableFilterTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableFilterTest.java
index 7f772e7c693fe..d3ed6b51b1382 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableFilterTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableFilterTest.java
@@ -66,6 +66,7 @@ public void setUp() {
 
     private final Predicate<String, Integer> predicate = (key, value) -> (value % 2) == 0;
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     private void doTestKTable(final StreamsBuilder builder,
                               final KTable<String, Integer> table2,
                               final KTable<String, Integer> table3,
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableImplTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableImplTest.java
index b979d3ecd7734..cac924e627453 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableImplTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableImplTest.java
@@ -83,6 +83,7 @@ public void setUp() {
         table = new StreamsBuilder().table("test");
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testKTable() {
         final StreamsBuilder builder = new StreamsBuilder();
@@ -151,6 +152,7 @@ public void testKTable() {
             processors.get(3).processed());
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testMaterializedKTable() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableInnerJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableInnerJoinTest.java
index 991ee5945296d..13caa9fea4494 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableInnerJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableInnerJoinTest.java
@@ -29,7 +29,6 @@
 import org.apache.kafka.streams.kstream.KTable;
 import org.apache.kafka.streams.kstream.Materialized;
 import org.apache.kafka.streams.processor.MockProcessorContext;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.internals.testutil.LogCaptureAppender;
 import org.apache.kafka.streams.state.KeyValueStore;
 import org.apache.kafka.streams.test.TestRecord;
@@ -54,6 +53,7 @@
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableKTableInnerJoinTest {
     private final static KeyValueTimestamp<?, ?>[] EMPTY = new KeyValueTimestamp[0];
 
@@ -251,7 +251,7 @@ public void shouldLogAndMeterSkippedRecordsDueToNullLeftKey() {
         final StreamsBuilder builder = new StreamsBuilder();
 
         @SuppressWarnings("unchecked")
-        final Processor<String, Change<String>> join = new KTableKTableInnerJoin<>(
+        final org.apache.kafka.streams.processor.Processor<String, Change<String>> join = new KTableKTableInnerJoin<>(
             (KTableImpl<String, String, String>) builder.table("left", Consumed.with(Serdes.String(), Serdes.String())),
             (KTableImpl<String, String, String>) builder.table("right", Consumed.with(Serdes.String(), Serdes.String())),
             null
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableLeftJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableLeftJoinTest.java
index 0d7f4b9444ece..0b14d8b76d4d7 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableLeftJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableLeftJoinTest.java
@@ -33,7 +33,6 @@
 import org.apache.kafka.streams.kstream.Materialized;
 import org.apache.kafka.streams.kstream.ValueMapper;
 import org.apache.kafka.streams.processor.MockProcessorContext;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.internals.testutil.LogCaptureAppender;
 import org.apache.kafka.streams.state.Stores;
 import org.apache.kafka.streams.test.TestRecord;
@@ -62,6 +61,7 @@
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableKTableLeftJoinTest {
     private final String topic1 = "topic1";
     private final String topic2 = "topic2";
@@ -517,7 +517,7 @@ public void shouldLogAndMeterSkippedRecordsDueToNullLeftKey() {
         final StreamsBuilder builder = new StreamsBuilder();
 
         @SuppressWarnings("unchecked")
-        final Processor<String, Change<String>> join = new KTableKTableLeftJoin<>(
+        final org.apache.kafka.streams.processor.Processor<String, Change<String>> join = new KTableKTableLeftJoin<>(
             (KTableImpl<String, String, String>) builder.table("left", Consumed.with(Serdes.String(), Serdes.String())),
             (KTableImpl<String, String, String>) builder.table("right", Consumed.with(Serdes.String(), Serdes.String())),
             null
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableOuterJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableOuterJoinTest.java
index e41d654073642..6b3cf3b746a00 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableOuterJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableOuterJoinTest.java
@@ -28,7 +28,6 @@
 import org.apache.kafka.streams.kstream.Consumed;
 import org.apache.kafka.streams.kstream.KTable;
 import org.apache.kafka.streams.processor.MockProcessorContext;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.internals.testutil.LogCaptureAppender;
 import org.apache.kafka.streams.test.TestRecord;
 import org.apache.kafka.test.MockApiProcessor;
@@ -52,6 +51,7 @@
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableKTableOuterJoinTest {
     private final String topic1 = "topic1";
     private final String topic2 = "topic2";
@@ -408,7 +408,7 @@ public void shouldLogAndMeterSkippedRecordsDueToNullLeftKey() {
         final StreamsBuilder builder = new StreamsBuilder();
 
         @SuppressWarnings("unchecked")
-        final Processor<String, Change<String>> join = new KTableKTableOuterJoin<>(
+        final org.apache.kafka.streams.processor.Processor<String, Change<String>> join = new KTableKTableOuterJoin<>(
                 (KTableImpl<String, String, String>) builder.table("left", Consumed.with(Serdes.String(), Serdes.String())),
                 (KTableImpl<String, String, String>) builder.table("right", Consumed.with(Serdes.String(), Serdes.String())),
                 null
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableRightJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableRightJoinTest.java
index 8e9ab437b3c2a..e8d9c6878b390 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableRightJoinTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableKTableRightJoinTest.java
@@ -22,7 +22,6 @@
 import org.apache.kafka.streams.StreamsConfig;
 import org.apache.kafka.streams.kstream.Consumed;
 import org.apache.kafka.streams.processor.MockProcessorContext;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.internals.testutil.LogCaptureAppender;
 import org.apache.kafka.test.StreamsTestUtils;
 import org.junit.Test;
@@ -32,6 +31,7 @@
 import static org.hamcrest.CoreMatchers.hasItem;
 import static org.hamcrest.MatcherAssert.assertThat;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableKTableRightJoinTest {
 
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.String(), Serdes.String());
@@ -41,7 +41,7 @@ public void shouldLogAndMeterSkippedRecordsDueToNullLeftKeyWithBuiltInMetricsVer
         final StreamsBuilder builder = new StreamsBuilder();
 
         @SuppressWarnings("unchecked")
-        final Processor<String, Change<String>> join = new KTableKTableRightJoin<>(
+        final org.apache.kafka.streams.processor.Processor<String, Change<String>> join = new KTableKTableRightJoin<>(
             (KTableImpl<String, String, String>) builder.table("left", Consumed.with(Serdes.String(), Serdes.String())),
             (KTableImpl<String, String, String>) builder.table("right", Consumed.with(Serdes.String(), Serdes.String())),
             null
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableMapKeysTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableMapKeysTest.java
index 548ac17d5622e..e761968db7ada 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableMapKeysTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableMapKeysTest.java
@@ -39,6 +39,7 @@
 public class KTableMapKeysTest {
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.Integer(), Serdes.String());
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testMapKeysConvertingToStream() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableMapValuesTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableMapValuesTest.java
index 384d57902187d..ff6e1b996a4ed 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableMapValuesTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableMapValuesTest.java
@@ -71,6 +71,7 @@ private void doTestKTable(final StreamsBuilder builder,
         }
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testKTable() {
         final StreamsBuilder builder = new StreamsBuilder();
@@ -85,6 +86,7 @@ public void testKTable() {
         doTestKTable(builder, topic1, supplier);
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testQueryableKTable() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableReduceTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableReduceTest.java
index 87d6e8745b3aa..0f5cc6b3e8b22 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableReduceTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableReduceTest.java
@@ -16,7 +16,6 @@
  */
 package org.apache.kafka.streams.kstream.internals;
 
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.internals.ProcessorNode;
 import org.apache.kafka.streams.state.TimestampedKeyValueStore;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
@@ -32,13 +31,14 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableReduceTest {
 
     @Test
     public void shouldAddAndSubtract() {
         final InternalMockProcessorContext<String, Change<Set<String>>> context = new InternalMockProcessorContext<>();
 
-        final Processor<String, Change<Set<String>>> reduceProcessor =
+        final org.apache.kafka.streams.processor.Processor<String, Change<Set<String>>> reduceProcessor =
             new KTableReduce<String, Set<String>>(
                 "myStore",
                 this::unionNotNullArgs,
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableSourceTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableSourceTest.java
index 1091d54deb4fc..e3371e059c694 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableSourceTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableSourceTest.java
@@ -59,6 +59,7 @@ public class KTableSourceTest {
     private final Consumed<String, String> stringConsumed = Consumed.with(Serdes.String(), Serdes.String());
     private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.String(), Serdes.String());
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     @Test
     public void testKTable() {
         final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableTransformValuesTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableTransformValuesTest.java
index 5ab151200c565..1690dc9423b64 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableTransformValuesTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableTransformValuesTest.java
@@ -33,7 +33,6 @@
 import org.apache.kafka.streams.kstream.ValueMapper;
 import org.apache.kafka.streams.kstream.ValueTransformerWithKey;
 import org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.internals.ForwardingDisabledProcessorContext;
 import org.apache.kafka.streams.processor.internals.InternalProcessorContext;
@@ -73,6 +72,7 @@
 import static org.junit.Assert.fail;
 
 @RunWith(EasyMockRunner.class)
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableTransformValuesTest {
     private static final String QUERYABLE_NAME = "queryable-store";
     private static final String INPUT_TOPIC = "inputTopic";
@@ -145,7 +145,7 @@ public void shouldInitializeTransformerWithForwardDisabledProcessorContext() {
         final NoOpValueTransformerWithKeySupplier<String, String> transformer = new NoOpValueTransformerWithKeySupplier<>();
         final KTableTransformValues<String, String, String> transformValues =
             new KTableTransformValues<>(parent, transformer, null);
-        final Processor<String, Change<String>> processor = transformValues.get();
+        final org.apache.kafka.streams.processor.Processor<String, Change<String>> processor = transformValues.get();
 
         processor.init(context);
 
@@ -157,7 +157,7 @@ public void shouldNotSendOldValuesByDefault() {
         final KTableTransformValues<String, String, String> transformValues =
             new KTableTransformValues<>(parent, new ExclamationValueTransformerSupplier(), null);
 
-        final Processor<String, Change<String>> processor = transformValues.get();
+        final org.apache.kafka.streams.processor.Processor<String, Change<String>> processor = transformValues.get();
         processor.init(context);
 
         context.forward("Key", new Change<>("Key->newValue!", null));
@@ -178,7 +178,7 @@ public void shouldSendOldValuesIfConfigured() {
         replay(parent);
 
         transformValues.enableSendingOldValues(true);
-        final Processor<String, Change<String>> processor = transformValues.get();
+        final org.apache.kafka.streams.processor.Processor<String, Change<String>> processor = transformValues.get();
         processor.init(context);
 
         context.forward("Key", new Change<>("Key->newValue!", "Key->oldValue!"));
@@ -301,7 +301,7 @@ public void shouldCloseTransformerOnProcessorClose() {
         expectLastCall();
         replay(mockSupplier, transformer);
 
-        final Processor<String, Change<String>> processor = transformValues.get();
+        final org.apache.kafka.streams.processor.Processor<String, Change<String>> processor = transformValues.get();
         processor.close();
 
         verify(transformer);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/SessionWindowedKStreamImplTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/SessionWindowedKStreamImplTest.java
index d6e56ba5b6128..28dbd188884ed 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/SessionWindowedKStreamImplTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/SessionWindowedKStreamImplTest.java
@@ -54,6 +54,7 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertThrows;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class SessionWindowedKStreamImplTest {
     private static final String TOPIC = "input";
     private final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/SlidingWindowedKStreamImplTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/SlidingWindowedKStreamImplTest.java
index d6b26bf2a7c59..ef69c9ff68325 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/SlidingWindowedKStreamImplTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/SlidingWindowedKStreamImplTest.java
@@ -54,6 +54,7 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertThrows;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class SlidingWindowedKStreamImplTest {
 
     private static final String TOPIC = "input";
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/TimeWindowedKStreamImplTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/TimeWindowedKStreamImplTest.java
index c35da00697ba5..0a847776bd187 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/TimeWindowedKStreamImplTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/TimeWindowedKStreamImplTest.java
@@ -52,6 +52,7 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertThrows;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class TimeWindowedKStreamImplTest {
     private static final String TOPIC = "input";
     private final StreamsBuilder builder = new StreamsBuilder();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionResolverJoinProcessorSupplierTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionResolverJoinProcessorSupplierTest.java
index 498e8edb68908..4a379d611d60d 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionResolverJoinProcessorSupplierTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/foreignkeyjoin/SubscriptionResolverJoinProcessorSupplierTest.java
@@ -24,7 +24,6 @@
 import org.apache.kafka.streams.kstream.internals.KTableValueGetter;
 import org.apache.kafka.streams.kstream.internals.KTableValueGetterSupplier;
 import org.apache.kafka.streams.processor.MockProcessorContext;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.state.ValueAndTimestamp;
 import org.apache.kafka.streams.state.internals.Murmur3;
@@ -38,6 +37,7 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.collection.IsEmptyCollection.empty;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class SubscriptionResolverJoinProcessorSupplierTest {
     private static final StringSerializer STRING_SERIALIZER = new StringSerializer();
     private static final ValueJoiner<String, String, String> JOINER =
@@ -83,7 +83,7 @@ public void shouldNotForwardWhenHashDoesNotMatch() {
                 JOINER,
                 leftJoin
             );
-        final Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
+        final org.apache.kafka.streams.processor.Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
         final MockProcessorContext context = new MockProcessorContext();
         processor.init(context);
         context.setRecordMetadata("topic", 0, 0, new RecordHeaders(), 0);
@@ -108,7 +108,7 @@ public void shouldIgnoreUpdateWhenLeftHasBecomeNull() {
                 JOINER,
                 leftJoin
             );
-        final Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
+        final org.apache.kafka.streams.processor.Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
         final MockProcessorContext context = new MockProcessorContext();
         processor.init(context);
         context.setRecordMetadata("topic", 0, 0, new RecordHeaders(), 0);
@@ -133,7 +133,7 @@ public void shouldForwardWhenHashMatches() {
                 JOINER,
                 leftJoin
             );
-        final Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
+        final org.apache.kafka.streams.processor.Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
         final MockProcessorContext context = new MockProcessorContext();
         processor.init(context);
         context.setRecordMetadata("topic", 0, 0, new RecordHeaders(), 0);
@@ -159,7 +159,7 @@ public void shouldEmitTombstoneForInnerJoinWhenRightIsNull() {
                 JOINER,
                 leftJoin
             );
-        final Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
+        final org.apache.kafka.streams.processor.Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
         final MockProcessorContext context = new MockProcessorContext();
         processor.init(context);
         context.setRecordMetadata("topic", 0, 0, new RecordHeaders(), 0);
@@ -185,7 +185,7 @@ public void shouldEmitResultForLeftJoinWhenRightIsNull() {
                 JOINER,
                 leftJoin
             );
-        final Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
+        final org.apache.kafka.streams.processor.Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
         final MockProcessorContext context = new MockProcessorContext();
         processor.init(context);
         context.setRecordMetadata("topic", 0, 0, new RecordHeaders(), 0);
@@ -211,7 +211,7 @@ public void shouldEmitTombstoneForLeftJoinWhenRightIsNullAndLeftIsNull() {
                 JOINER,
                 leftJoin
             );
-        final Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
+        final org.apache.kafka.streams.processor.Processor<String, SubscriptionResponseWrapper<String>> processor = processorSupplier.get();
         final MockProcessorContext context = new MockProcessorContext();
         processor.init(context);
         context.setRecordMetadata("topic", 0, 0, new RecordHeaders(), 0);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/graph/GraphGraceSearchUtilTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/graph/GraphGraceSearchUtilTest.java
index 0d75452a798fc..a898338f5fc37 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/graph/GraphGraceSearchUtilTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/graph/GraphGraceSearchUtilTest.java
@@ -22,7 +22,6 @@
 import org.apache.kafka.streams.kstream.internals.KStreamSessionWindowAggregate;
 import org.apache.kafka.streams.kstream.internals.KStreamWindowAggregate;
 import org.apache.kafka.streams.kstream.internals.TimeWindow;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.state.StoreBuilder;
 import org.junit.Test;
@@ -32,6 +31,7 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.fail;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class GraphGraceSearchUtilTest {
     @Test
     public void shouldThrowOnNull() {
@@ -50,7 +50,7 @@ public void shouldFailIfThereIsNoGraceAncestor() {
         final StatefulProcessorNode<String, Long> gracelessAncestor = new StatefulProcessorNode<>(
             "stateful",
             new ProcessorParameters<>(
-                () -> new Processor<String, Long>() {
+                () -> new org.apache.kafka.streams.processor.Processor<String, Long>() {
                     @Override
                     public void init(final ProcessorContext context) {}
 
@@ -134,7 +134,7 @@ public void shouldExtractGraceFromSessionAncestorThroughStatefulParent() {
         final StatefulProcessorNode<String, Long> statefulParent = new StatefulProcessorNode<>(
             "stateful",
             new ProcessorParameters<>(
-                () -> new Processor<String, Long>() {
+                () -> new org.apache.kafka.streams.processor.Processor<String, Long>() {
                     @Override
                     public void init(final ProcessorContext context) {}
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/graph/TableProcessorNodeTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/graph/TableProcessorNodeTest.java
index a2c4938336376..99be7f85498ab 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/graph/TableProcessorNodeTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/graph/TableProcessorNodeTest.java
@@ -17,16 +17,15 @@
 
 package org.apache.kafka.streams.kstream.internals.graph;
 
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.ProcessorContext;
 import org.junit.Test;
 
 import static org.junit.Assert.assertTrue;
 
 public class TableProcessorNodeTest {
-    private static class TestProcessor extends AbstractProcessor<String, String> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private static class TestProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<String, String> {
         @Override
-        public void init(final ProcessorContext context) {
+        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
         }
 
         @Override
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorMetricsTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorMetricsTest.java
index fa4eada2458ea..4db1342a1e627 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorMetricsTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorMetricsTest.java
@@ -26,7 +26,6 @@
 import org.apache.kafka.streams.kstream.Suppressed;
 import org.apache.kafka.streams.kstream.internals.Change;
 import org.apache.kafka.streams.kstream.internals.KTableImpl;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.StateStore;
 import org.apache.kafka.streams.processor.StateStoreContext;
 import org.apache.kafka.streams.processor.TaskId;
@@ -50,6 +49,7 @@
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.core.Is.is;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableSuppressProcessorMetricsTest {
     private static final long ARBITRARY_LONG = 5L;
     private static final TaskId TASK_ID = new TaskId(0, 0);
@@ -134,7 +134,7 @@ public void shouldRecordMetricsWithBuiltInMetricsVersionLatest() {
             .build();
 
         final KTableImpl<String, ?, Long> mock = EasyMock.mock(KTableImpl.class);
-        final Processor<String, Change<Long>> processor =
+        final org.apache.kafka.streams.processor.Processor<String, Change<Long>> processor =
             new KTableSuppressProcessorSupplier<>(
                 (SuppressedInternal<String>) Suppressed.<String>untilTimeLimit(Duration.ofDays(100), maxRecords(1)),
                 storeName,
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorTest.java
index 401996588e591..23b91c5d1c21a 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/suppress/KTableSuppressProcessorTest.java
@@ -30,7 +30,6 @@
 import org.apache.kafka.streams.kstream.internals.SessionWindow;
 import org.apache.kafka.streams.kstream.internals.TimeWindow;
 import org.apache.kafka.streams.processor.MockProcessorContext;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.StateStore;
 import org.apache.kafka.streams.processor.StateStoreContext;
 import org.apache.kafka.streams.processor.internals.ProcessorNode;
@@ -60,13 +59,14 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.fail;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class KTableSuppressProcessorTest {
     private static final long ARBITRARY_LONG = 5L;
 
     private static final Change<Long> ARBITRARY_CHANGE = new Change<>(7L, 14L);
 
     private static class Harness<K, V> {
-        private final Processor<K, Change<V>> processor;
+        private final org.apache.kafka.streams.processor.Processor<K, Change<V>> processor;
         private final MockInternalProcessorContext context;
 
 
@@ -81,7 +81,7 @@ private static class Harness<K, V> {
                 .build();
 
             final KTableImpl<K, ?, V> parent = EasyMock.mock(KTableImpl.class);
-            final Processor<K, Change<V>> processor =
+            final org.apache.kafka.streams.processor.Processor<K, Change<V>> processor =
                 new KTableSuppressProcessorSupplier<>((SuppressedInternal<K>) suppressed, storeName, parent).get();
 
             final MockInternalProcessorContext context = new MockInternalProcessorContext();
diff --git a/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorContextImplTest.java b/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorContextImplTest.java
index 9412e55e0ff60..e49f1fa8b0180 100644
--- a/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorContextImplTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorContextImplTest.java
@@ -21,7 +21,6 @@
 import org.apache.kafka.common.utils.Bytes;
 import org.apache.kafka.streams.StreamsConfig;
 import org.apache.kafka.streams.kstream.Windowed;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.PunctuationType;
 import org.apache.kafka.streams.processor.StateStore;
@@ -717,7 +716,7 @@ private void initStateStoreMock(final StateStore stateStore) {
     }
 
     private <T extends StateStore> void doTest(final String name, final Consumer<T> checker) {
-        final Processor<String, Long> processor = new Processor<String, Long>() {
+        @SuppressWarnings("deprecation") final org.apache.kafka.streams.processor.Processor<String, Long> processor = new org.apache.kafka.streams.processor.Processor<String, Long>() {
             @Override
             public void init(final ProcessorContext context) {
                 final T store = context.getStateStore(name);
diff --git a/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorNodeTest.java b/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorNodeTest.java
index 33d5c4d909caa..511938da84f16 100644
--- a/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorNodeTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorNodeTest.java
@@ -25,7 +25,6 @@
 import org.apache.kafka.streams.Topology;
 import org.apache.kafka.streams.TopologyTestDriver;
 import org.apache.kafka.streams.errors.StreamsException;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.api.Record;
 import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
@@ -62,7 +61,8 @@ public void shouldThrowStreamsExceptionIfExceptionCaughtDuringClose() {
         assertThrows(StreamsException.class, () -> node.init(null));
     }
 
-    private static class ExceptionalProcessor implements Processor<Object, Object> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private static class ExceptionalProcessor implements org.apache.kafka.streams.processor.Processor<Object, Object> {
         @Override
         public void init(final ProcessorContext context) {
             throw new RuntimeException();
@@ -79,7 +79,8 @@ public void close() {
         }
     }
 
-    private static class NoOpProcessor implements Processor<Object, Object> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private static class NoOpProcessor implements org.apache.kafka.streams.processor.Processor<Object, Object> {
         @Override
         public void init(final ProcessorContext context) {
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorTopologyTest.java b/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorTopologyTest.java
index 6f384a77b0a2a..b92a46840af35 100644
--- a/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorTopologyTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorTopologyTest.java
@@ -32,7 +32,6 @@
 import org.apache.kafka.streams.Topology;
 import org.apache.kafka.streams.TopologyTestDriver;
 import org.apache.kafka.streams.TopologyWrapper;
-import org.apache.kafka.streams.processor.AbstractProcessor;
 import org.apache.kafka.streams.processor.StreamPartitioner;
 import org.apache.kafka.streams.processor.TimestampExtractor;
 import org.apache.kafka.streams.processor.api.Processor;
@@ -877,7 +876,8 @@ public void process(final Record<String, String> record) {
     /**
      * A processor that stores each key-value pair in an in-memory key-value store registered with the context.
      */
-    protected static class OldAPIStatefulProcessor extends AbstractProcessor<String, String> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    protected static class OldAPIStatefulProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<String, String> {
         private KeyValueStore<String, String> store;
         private final String storeName;
 
@@ -919,10 +919,12 @@ public void process(final Record<String, String> record) {
         }
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     private <K, V> org.apache.kafka.streams.processor.ProcessorSupplier<K, V> define(final org.apache.kafka.streams.processor.Processor<K, V> processor) {
         return () -> processor;
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     private <K, V> org.apache.kafka.streams.processor.ProcessorSupplier<K, V> defineWithStoresOldAPI(final Supplier<org.apache.kafka.streams.processor.Processor<K, V>> supplier,
                                                                                                      final Set<StoreBuilder<?>> stores) {
         return new org.apache.kafka.streams.processor.ProcessorSupplier<K, V>() {
diff --git a/streams/src/test/java/org/apache/kafka/streams/processor/internals/PunctuationQueueTest.java b/streams/src/test/java/org/apache/kafka/streams/processor/internals/PunctuationQueueTest.java
index ac56924844883..cde573a982e25 100644
--- a/streams/src/test/java/org/apache/kafka/streams/processor/internals/PunctuationQueueTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/processor/internals/PunctuationQueueTest.java
@@ -16,7 +16,6 @@
  */
 package org.apache.kafka.streams.processor.internals;
 
-import org.apache.kafka.streams.processor.AbstractProcessor;
 import org.apache.kafka.streams.processor.Cancellable;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.PunctuationType;
@@ -141,7 +140,8 @@ public void punctuate(final ProcessorNode node, final long timestamp, final Punc
         assertEquals(1, node.mockProcessor.punctuatedStreamTime().size());
     }
 
-    private static class TestProcessor extends AbstractProcessor<String, String> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private static class TestProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<String, String> {
 
         @Override
         public void init(final ProcessorContext context) {}
diff --git a/streams/src/test/java/org/apache/kafka/streams/processor/internals/RepartitionOptimizingTest.java b/streams/src/test/java/org/apache/kafka/streams/processor/internals/RepartitionOptimizingTest.java
index bd4829989a9e4..3b7eb784f7c20 100644
--- a/streams/src/test/java/org/apache/kafka/streams/processor/internals/RepartitionOptimizingTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/processor/internals/RepartitionOptimizingTest.java
@@ -44,7 +44,6 @@
 import org.apache.kafka.streams.kstream.Produced;
 import org.apache.kafka.streams.kstream.Reducer;
 import org.apache.kafka.streams.kstream.StreamJoined;
-import org.apache.kafka.streams.processor.AbstractProcessor;
 import org.apache.kafka.streams.state.Stores;
 import org.apache.kafka.test.StreamsTestUtils;
 import org.junit.After;
@@ -135,6 +134,7 @@ public void shouldSendCorrectResults_NO_OPTIMIZATION() {
     }
 
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     private void runTest(final String optimizationConfig, final int expectedNumberRepartitionTopics) {
 
         final StreamsBuilder builder = new StreamsBuilder();
@@ -257,7 +257,8 @@ private List<KeyValue<String, String>> getKeyValues() {
         return keyValueList;
     }
 
-    private static class SimpleProcessor extends AbstractProcessor<String, String> {
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+    private static class SimpleProcessor extends org.apache.kafka.streams.processor.AbstractProcessor<String, String> {
 
         final List<String> valueList;
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/processor/internals/StreamThreadTest.java b/streams/src/test/java/org/apache/kafka/streams/processor/internals/StreamThreadTest.java
index 89846d86c0d00..b8e5d23eef908 100644
--- a/streams/src/test/java/org/apache/kafka/streams/processor/internals/StreamThreadTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/processor/internals/StreamThreadTest.java
@@ -1809,6 +1809,7 @@ public void shouldNotCreateStandbyTaskIfStateStoresHaveLoggingDisabled() {
     }
 
     @Test
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     public void shouldPunctuateActiveTask() {
         final List<Long> punctuatedStreamTime = new ArrayList<>();
         final List<Long> punctuatedWallClockTime = new ArrayList<>();
@@ -1879,6 +1880,7 @@ public void process(final Object key, final Object value) {}
     }
 
     @Test
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     public void shouldPunctuateWithTimestampPreservedInProcessorContext() {
         final org.apache.kafka.streams.kstream.TransformerSupplier<Object, Object, KeyValue<Object, Object>> punctuateProcessor =
             () -> new org.apache.kafka.streams.kstream.Transformer<Object, Object, KeyValue<Object, Object>>() {
diff --git a/streams/src/test/java/org/apache/kafka/streams/tests/EosTestClient.java b/streams/src/test/java/org/apache/kafka/streams/tests/EosTestClient.java
index eb81a71800b7c..18d945855463f 100644
--- a/streams/src/test/java/org/apache/kafka/streams/tests/EosTestClient.java
+++ b/streams/src/test/java/org/apache/kafka/streams/tests/EosTestClient.java
@@ -99,6 +99,7 @@ public void start() {
         }
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     private KafkaStreams createKafkaStreams(final Properties props) {
         props.put(StreamsConfig.APPLICATION_ID_CONFIG, APP_ID);
         props.put(StreamsConfig.NUM_STREAM_THREADS_CONFIG, 1);
diff --git a/streams/src/test/java/org/apache/kafka/streams/tests/SmokeTestClient.java b/streams/src/test/java/org/apache/kafka/streams/tests/SmokeTestClient.java
index 2e53d580d5292..4882fdd5bdf5a 100644
--- a/streams/src/test/java/org/apache/kafka/streams/tests/SmokeTestClient.java
+++ b/streams/src/test/java/org/apache/kafka/streams/tests/SmokeTestClient.java
@@ -160,6 +160,7 @@ private Properties getStreamsConfig(final Properties props) {
         return fullProps;
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     public Topology getTopology() {
         final StreamsBuilder builder = new StreamsBuilder();
         final Consumed<String, Integer> stringIntConsumed = Consumed.with(stringSerde, intSerde);
diff --git a/streams/src/test/java/org/apache/kafka/streams/tests/SmokeTestUtil.java b/streams/src/test/java/org/apache/kafka/streams/tests/SmokeTestUtil.java
index e8ec04c23ca52..1222a81b2fb51 100644
--- a/streams/src/test/java/org/apache/kafka/streams/tests/SmokeTestUtil.java
+++ b/streams/src/test/java/org/apache/kafka/streams/tests/SmokeTestUtil.java
@@ -23,26 +23,24 @@
 import org.apache.kafka.streams.kstream.Initializer;
 import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.Windowed;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 
 import java.time.Instant;
 
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
 public class SmokeTestUtil {
 
     final static int END = Integer.MAX_VALUE;
 
-    static ProcessorSupplier<Object, Object> printProcessorSupplier(final String topic) {
+    static org.apache.kafka.streams.processor.ProcessorSupplier<Object, Object> printProcessorSupplier(final String topic) {
         return printProcessorSupplier(topic, "");
     }
 
-    static ProcessorSupplier<Object, Object> printProcessorSupplier(final String topic, final String name) {
-        return new ProcessorSupplier<Object, Object>() {
+    static org.apache.kafka.streams.processor.ProcessorSupplier<Object, Object> printProcessorSupplier(final String topic, final String name) {
+        return new org.apache.kafka.streams.processor.ProcessorSupplier<Object, Object>() {
             @Override
-            public Processor<Object, Object> get() {
-                return new AbstractProcessor<Object, Object>() {
+            public org.apache.kafka.streams.processor.Processor<Object, Object> get() {
+                return new org.apache.kafka.streams.processor.AbstractProcessor<Object, Object>() {
                     private int numRecordsProcessed = 0;
                     private long smallestOffset = Long.MAX_VALUE;
                     private long largestOffset = Long.MIN_VALUE;
diff --git a/streams/src/test/java/org/apache/kafka/streams/tests/StreamsUpgradeTest.java b/streams/src/test/java/org/apache/kafka/streams/tests/StreamsUpgradeTest.java
index 2ad07f2fa3e4a..1ea5c0f2b0c4f 100644
--- a/streams/src/test/java/org/apache/kafka/streams/tests/StreamsUpgradeTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/tests/StreamsUpgradeTest.java
@@ -89,6 +89,7 @@ public static void main(final String[] args) throws Exception {
         });
     }
 
+    @SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
     public static KafkaStreams buildStreams(final Properties streamsProperties) {
         final StreamsBuilder builder = new StreamsBuilder();
         final KStream<Void, Void> dataStream = builder.stream("data");
diff --git a/streams/src/test/java/org/apache/kafka/test/MockProcessor.java b/streams/src/test/java/org/apache/kafka/test/MockProcessor.java
index f18b763f0fe3e..a3bb87d3034dc 100644
--- a/streams/src/test/java/org/apache/kafka/test/MockProcessor.java
+++ b/streams/src/test/java/org/apache/kafka/test/MockProcessor.java
@@ -17,7 +17,6 @@
 package org.apache.kafka.test;
 
 import org.apache.kafka.streams.KeyValueTimestamp;
-import org.apache.kafka.streams.processor.AbstractProcessor;
 import org.apache.kafka.streams.processor.Cancellable;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.PunctuationType;
@@ -28,7 +27,8 @@
 import java.util.List;
 import java.util.Map;
 
-public class MockProcessor<K, V> extends AbstractProcessor<K, V> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public class MockProcessor<K, V> extends org.apache.kafka.streams.processor.AbstractProcessor<K, V> {
     private final MockApiProcessor<K, V, Object, Object> delegate;
 
     public MockProcessor(final PunctuationType punctuationType,
diff --git a/streams/src/test/java/org/apache/kafka/test/MockProcessorSupplier.java b/streams/src/test/java/org/apache/kafka/test/MockProcessorSupplier.java
index 7b73dd3d5b7af..c6b70f2763d82 100644
--- a/streams/src/test/java/org/apache/kafka/test/MockProcessorSupplier.java
+++ b/streams/src/test/java/org/apache/kafka/test/MockProcessorSupplier.java
@@ -16,8 +16,6 @@
  */
 package org.apache.kafka.test;
 
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
 import org.apache.kafka.streams.processor.PunctuationType;
 
 import java.util.ArrayList;
@@ -25,7 +23,8 @@
 
 import static org.junit.Assert.assertEquals;
 
-public class MockProcessorSupplier<K, V> implements ProcessorSupplier<K, V> {
+@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
+public class MockProcessorSupplier<K, V> implements org.apache.kafka.streams.processor.ProcessorSupplier<K, V> {
 
     private final long scheduleInterval;
     private final PunctuationType punctuationType;
@@ -45,7 +44,7 @@ public MockProcessorSupplier(final long scheduleInterval, final PunctuationType
     }
 
     @Override
-    public Processor<K, V> get() {
+    public org.apache.kafka.streams.processor.Processor<K, V> get() {
         final MockProcessor<K, V> processor = new MockProcessor<>(punctuationType, scheduleInterval);
 
         // to keep tests simple, ignore calls from ApiUtils.checkSupplier
diff --git a/streams/streams-scala/src/main/scala/org/apache/kafka/streams/scala/kstream/KStream.scala b/streams/streams-scala/src/main/scala/org/apache/kafka/streams/scala/kstream/KStream.scala
index 4d63e67268718..d3f83e0e20a9e 100644
--- a/streams/streams-scala/src/main/scala/org/apache/kafka/streams/scala/kstream/KStream.scala
+++ b/streams/streams-scala/src/main/scala/org/apache/kafka/streams/scala/kstream/KStream.scala
@@ -27,7 +27,8 @@ import org.apache.kafka.streams.kstream.{
   ValueTransformerWithKeySupplier,
   KStream => KStreamJ
 }
-import org.apache.kafka.streams.processor.{Processor, ProcessorSupplier, TopicNameExtractor}
+import org.apache.kafka.streams.processor.TopicNameExtractor
+import org.apache.kafka.streams.processor.api.ProcessorSupplier
 import org.apache.kafka.streams.scala.FunctionsCompatConversions.{
   FlatValueMapperFromFunction,
   FlatValueMapperWithKeyFromFunction,
@@ -789,11 +790,31 @@ class KStream[K, V](val inner: KStreamJ[K, V]) {
    * @param stateStoreNames   the names of the state store used by the processor
    * @see `org.apache.kafka.streams.kstream.KStream#process`
    */
-  def process(processorSupplier: () => Processor[K, V], stateStoreNames: String*): Unit = {
-    val processorSupplierJ: ProcessorSupplier[K, V] = () => processorSupplier()
+  @deprecated(since = "3.0", message = "Use process(ProcessorSupplier, String*) instead.")
+  def process(processorSupplier: () => org.apache.kafka.streams.processor.Processor[K, V],
+              stateStoreNames: String*): Unit = {
+    val processorSupplierJ: org.apache.kafka.streams.processor.ProcessorSupplier[K, V] = () => processorSupplier()
     inner.process(processorSupplierJ, stateStoreNames: _*)
   }
 
+  /**
+   * Process all records in this stream, one record at a time, by applying a `Processor` (provided by the given
+   * `processorSupplier`).
+   * In order to assign a state, the state must be created and added via `addStateStore` before they can be connected
+   * to the `Processor`.
+   * It's not required to connect global state stores that are added via `addGlobalStore`;
+   * read-only access to global state stores is available by default.
+   *
+   * Note that this overload takes a ProcessorSupplier instead of a Function to avoid post-erasure ambiguity with
+   * the older (deprecated) overload.
+   *
+   * @param processorSupplier a supplier for [[org.apache.kafka.streams.processor.api.Processor]]
+   * @param stateStoreNames   the names of the state store used by the processor
+   * @see `org.apache.kafka.streams.kstream.KStream#process`
+   */
+  def process(processorSupplier: ProcessorSupplier[K, V, Void, Void], stateStoreNames: String*): Unit =
+    inner.process(processorSupplier, stateStoreNames: _*)
+
   /**
    * Process all records in this stream, one record at a time, by applying a `Processor` (provided by the given
    * `processorSupplier`).
@@ -807,11 +828,33 @@ class KStream[K, V](val inner: KStreamJ[K, V]) {
    * @param stateStoreNames   the names of the state store used by the processor
    * @see `org.apache.kafka.streams.kstream.KStream#process`
    */
-  def process(processorSupplier: () => Processor[K, V], named: Named, stateStoreNames: String*): Unit = {
-    val processorSupplierJ: ProcessorSupplier[K, V] = () => processorSupplier()
+  @deprecated(since = "3.0", message = "Use process(ProcessorSupplier, String*) instead.")
+  def process(processorSupplier: () => org.apache.kafka.streams.processor.Processor[K, V],
+              named: Named,
+              stateStoreNames: String*): Unit = {
+    val processorSupplierJ: org.apache.kafka.streams.processor.ProcessorSupplier[K, V] = () => processorSupplier()
     inner.process(processorSupplierJ, named, stateStoreNames: _*)
   }
 
+  /**
+   * Process all records in this stream, one record at a time, by applying a `Processor` (provided by the given
+   * `processorSupplier`).
+   * In order to assign a state, the state must be created and added via `addStateStore` before they can be connected
+   * to the `Processor`.
+   * It's not required to connect global state stores that are added via `addGlobalStore`;
+   * read-only access to global state stores is available by default.
+   *
+   * Note that this overload takes a ProcessorSupplier instead of a Function to avoid post-erasure ambiguity with
+   * the older (deprecated) overload.
+   *
+   * @param processorSupplier a supplier for [[org.apache.kafka.streams.processor.api.Processor]]
+   * @param named             a [[Named]] config used to name the processor in the topology
+   * @param stateStoreNames   the names of the state store used by the processor
+   * @see `org.apache.kafka.streams.kstream.KStream#process`
+   */
+  def process(processorSupplier: ProcessorSupplier[K, V, Void, Void], named: Named, stateStoreNames: String*): Unit =
+    inner.process(processorSupplier, named, stateStoreNames: _*)
+
   /**
    * Group the records by their current key into a [[KGroupedStream]]
    * <p>
diff --git a/streams/streams-scala/src/test/scala/org/apache/kafka/streams/scala/TopologyTest.scala b/streams/streams-scala/src/test/scala/org/apache/kafka/streams/scala/TopologyTest.scala
index 1dc2e76561520..9653ddb1e5790 100644
--- a/streams/streams-scala/src/test/scala/org/apache/kafka/streams/scala/TopologyTest.scala
+++ b/streams/streams-scala/src/test/scala/org/apache/kafka/streams/scala/TopologyTest.scala
@@ -20,24 +20,24 @@ import java.time.Duration
 import java.util
 import java.util.{Locale, Properties}
 import java.util.regex.Pattern
-
 import org.apache.kafka.common.serialization.{Serdes => SerdesJ}
 import org.apache.kafka.streams.kstream.{
   Aggregator,
   Initializer,
   JoinWindows,
   KeyValueMapper,
+  Reducer,
+  Transformer,
+  ValueJoiner,
+  ValueMapper,
   KGroupedStream => KGroupedStreamJ,
   KStream => KStreamJ,
   KTable => KTableJ,
   Materialized => MaterializedJ,
-  Reducer,
-  StreamJoined => StreamJoinedJ,
-  Transformer,
-  ValueJoiner,
-  ValueMapper
+  StreamJoined => StreamJoinedJ
 }
-import org.apache.kafka.streams.processor.{AbstractProcessor, ProcessorContext, ProcessorSupplier}
+import org.apache.kafka.streams.processor.{api, ProcessorContext}
+import org.apache.kafka.streams.processor.api.{Processor, ProcessorSupplier}
 import org.apache.kafka.streams.scala.ImplicitConversions._
 import org.apache.kafka.streams.scala.serialization.{Serdes => NewSerdes}
 import org.apache.kafka.streams.scala.serialization.Serdes._
@@ -359,7 +359,7 @@ class TopologyTest {
       mappedStream
         .filter((k: String, _: String) => k == "B")
         .mapValues((v: String) => v.toUpperCase(Locale.getDefault))
-        .process(() => new SimpleProcessor(processorValueCollector))
+        .process(new SimpleProcessorSupplier(processorValueCollector))
 
       val stream2 = mappedStream.groupByKey
         .aggregate(0)(aggregator)(Materialized.`with`(NewSerdes.stringSerde, NewSerdes.intSerde))
@@ -402,7 +402,7 @@ class TopologyTest {
       val reducer: Reducer[String] = (v1, v2) => v1 + ":" + v2
       val valueMapper: ValueMapper[String, String] = v => v.toUpperCase(Locale.getDefault)
       val processorValueCollector = new util.ArrayList[String]
-      val processorSupplier: ProcessorSupplier[String, String] = () => new SimpleProcessor(processorValueCollector)
+      val processorSupplier = new SimpleProcessorSupplier(processorValueCollector)
       val valueJoiner2: ValueJoiner[String, Integer, String] = (value1, value2) => value1 + ":" + value2.toString
       val valueJoiner3: ValueJoiner[String, String, String] = (value1, value2) => value1 + ":" + value2
 
@@ -457,9 +457,10 @@ class TopologyTest {
     assertEquals(getTopologyScala.build(props).describe.toString, getTopologyJava.build(props).describe.toString)
   }
 
-  private class SimpleProcessor private[TopologyTest] (val valueList: util.List[String])
-      extends AbstractProcessor[String, String] {
-    override def process(key: String, value: String): Unit =
-      valueList.add(value)
+  private class SimpleProcessorSupplier private[TopologyTest] (val valueList: util.List[String])
+      extends ProcessorSupplier[String, String, Void, Void] {
+
+    override def get(): Processor[String, String, Void, Void] =
+      (record: api.Record[String, String]) => valueList.add(record.value())
   }
 }
diff --git a/streams/test-utils/src/main/java/org/apache/kafka/streams/TopologyTestDriver.java b/streams/test-utils/src/main/java/org/apache/kafka/streams/TopologyTestDriver.java
index 7366e7063f994..78924b543be91 100644
--- a/streams/test-utils/src/main/java/org/apache/kafka/streams/TopologyTestDriver.java
+++ b/streams/test-utils/src/main/java/org/apache/kafka/streams/TopologyTestDriver.java
@@ -195,7 +195,7 @@
  * trigger manually via {@link #advanceWallClockTime(Duration)}.
  * <p>
  * Finally, when completed, make sure your tests {@link #close()} the driver to release all resources and
- * {@link org.apache.kafka.streams.processor.Processor processors}.
+ * {@link org.apache.kafka.streams.processor.api.Processor processors}.
  *
  * <h2>Processor state</h2>
  * <p>
diff --git a/streams/test-utils/src/main/java/org/apache/kafka/streams/processor/MockProcessorContext.java b/streams/test-utils/src/main/java/org/apache/kafka/streams/processor/MockProcessorContext.java
index 577f94f467429..0c81e3e9593b3 100644
--- a/streams/test-utils/src/main/java/org/apache/kafka/streams/processor/MockProcessorContext.java
+++ b/streams/test-utils/src/main/java/org/apache/kafka/streams/processor/MockProcessorContext.java
@@ -56,6 +56,7 @@
  * If you require more automated tests, we recommend wrapping your {@link Processor} in a minimal source-processor-sink
  * {@link Topology} and using the {@link TopologyTestDriver}.
  */
+@SuppressWarnings("deprecation") // not deprecating old PAPI Context, since it is still in use by Transformers.
 public class MockProcessorContext implements ProcessorContext, RecordCollector.Supplier {
     // Immutable fields ================================================
     private final StreamsMetricsImpl metrics;
diff --git a/streams/test-utils/src/test/java/org/apache/kafka/streams/MockProcessorContextTest.java b/streams/test-utils/src/test/java/org/apache/kafka/streams/MockProcessorContextTest.java
index 6e3d9315266c5..e76cb4fe9a7e1 100644
--- a/streams/test-utils/src/test/java/org/apache/kafka/streams/MockProcessorContextTest.java
+++ b/streams/test-utils/src/test/java/org/apache/kafka/streams/MockProcessorContextTest.java
@@ -18,10 +18,8 @@
 
 import org.apache.kafka.common.header.internals.RecordHeaders;
 import org.apache.kafka.common.serialization.Serdes;
-import org.apache.kafka.streams.processor.AbstractProcessor;
 import org.apache.kafka.streams.processor.MockProcessorContext;
 import org.apache.kafka.streams.processor.MockProcessorContext.CapturedForward;
-import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.processor.PunctuationType;
 import org.apache.kafka.streams.processor.Punctuator;
@@ -48,7 +46,7 @@
 public class MockProcessorContextTest {
     @Test
     public void shouldCaptureOutputRecords() {
-        final AbstractProcessor<String, Long> processor = new AbstractProcessor<String, Long>() {
+        final org.apache.kafka.streams.processor.AbstractProcessor<String, Long> processor = new org.apache.kafka.streams.processor.AbstractProcessor<String, Long>() {
             @Override
             public void process(final String key, final Long value) {
                 context().forward(key + value, key.length() + value);
@@ -73,7 +71,7 @@ public void process(final String key, final Long value) {
 
     @Test
     public void shouldCaptureOutputRecordsUsingTo() {
-        final AbstractProcessor<String, Long> processor = new AbstractProcessor<String, Long>() {
+        final org.apache.kafka.streams.processor.AbstractProcessor<String, Long> processor = new org.apache.kafka.streams.processor.AbstractProcessor<String, Long>() {
             @Override
             public void process(final String key, final Long value) {
                 context().forward(key + value, key.length() + value, To.all());
@@ -99,7 +97,7 @@ public void process(final String key, final Long value) {
 
     @Test
     public void shouldCaptureRecordsOutputToChildByName() {
-        final AbstractProcessor<String, Long> processor = new AbstractProcessor<String, Long>() {
+        final org.apache.kafka.streams.processor.AbstractProcessor<String, Long> processor = new org.apache.kafka.streams.processor.AbstractProcessor<String, Long>() {
             private int count = 0;
 
             @Override
@@ -161,7 +159,7 @@ public void process(final String key, final Long value) {
 
     @Test
     public void shouldCaptureCommitsAndAllowReset() {
-        final AbstractProcessor<String, Long> processor = new AbstractProcessor<String, Long>() {
+        final org.apache.kafka.streams.processor.AbstractProcessor<String, Long> processor = new org.apache.kafka.streams.processor.AbstractProcessor<String, Long>() {
             private int count = 0;
 
             @Override
@@ -192,7 +190,7 @@ public void process(final String key, final Long value) {
 
     @Test
     public void shouldStoreAndReturnStateStores() {
-        final AbstractProcessor<String, Long> processor = new AbstractProcessor<String, Long>() {
+        final org.apache.kafka.streams.processor.AbstractProcessor<String, Long> processor = new org.apache.kafka.streams.processor.AbstractProcessor<String, Long>() {
             @Override
             public void process(final String key, final Long value) {
                 final KeyValueStore<String, Long> stateStore = context().getStateStore("my-state");
@@ -227,7 +225,7 @@ public void shouldCaptureApplicationAndRecordMetadata() {
         final Properties config = new Properties();
         config.put(StreamsConfig.APPLICATION_ID_CONFIG, "testMetadata");
 
-        final AbstractProcessor<String, Object> processor = new AbstractProcessor<String, Object>() {
+        final org.apache.kafka.streams.processor.AbstractProcessor<String, Object> processor = new org.apache.kafka.streams.processor.AbstractProcessor<String, Object>() {
             @Override
             public void process(final String key, final Object value) {
                 context().forward("appId", context().applicationId());
@@ -313,7 +311,7 @@ public void process(final String key, final Object value) {
 
     @Test
     public void shouldCapturePunctuator() {
-        final Processor<String, Long> processor = new Processor<String, Long>() {
+        final org.apache.kafka.streams.processor.Processor<String, Long> processor = new org.apache.kafka.streams.processor.Processor<String, Long>() {
             @Override
             public void init(final ProcessorContext context) {
                 context.schedule(