diff --git a/abstract-document/src/main/java/com/iluwatar/abstractdocument/AbstractDocument.java b/abstract-document/src/main/java/com/iluwatar/abstractdocument/AbstractDocument.java
index 36a946cc9eca..a9910a2dc807 100644
--- a/abstract-document/src/main/java/com/iluwatar/abstractdocument/AbstractDocument.java
+++ b/abstract-document/src/main/java/com/iluwatar/abstractdocument/AbstractDocument.java
@@ -54,9 +54,9 @@ public Object get(String key) {
 
   @Override
   public <T> Stream<T> children(String key, Function<Map<String, Object>, T> constructor) {
-    Optional<List<Map<String, Object>>> any = Stream.of(get(key)).filter(el -> el != null)
+    Optional<List<Map<String, Object>>> any = Stream.of(get(key)).parallel().filter(el -> el != null)
         .map(el -> (List<Map<String, Object>>) el).findAny();
-    return any.isPresent() ? any.get().stream().map(constructor) : Stream.empty();
+    return any.isPresent() ? any.get().parallelStream().map(constructor) : Stream.empty();
   }
 
   @Override
diff --git a/dao/src/main/java/com/iluwatar/dao/DbCustomerDao.java b/dao/src/main/java/com/iluwatar/dao/DbCustomerDao.java
index fa2e411dab56..2a6ac91c2838 100644
--- a/dao/src/main/java/com/iluwatar/dao/DbCustomerDao.java
+++ b/dao/src/main/java/com/iluwatar/dao/DbCustomerDao.java
@@ -86,7 +86,7 @@ public boolean tryAdvance(Consumer<? super Customer> action) {
             throw new RuntimeException(e); // NOSONAR
           }
         }
-      }, false).onClose(() -> mutedClose(connection, statement, resultSet));
+      }, false).parallel().onClose(() -> mutedClose(connection, statement, resultSet));
     } catch (SQLException e) {
       throw new CustomException(e.getMessage(), e);
     }
diff --git a/dao/src/main/java/com/iluwatar/dao/InMemoryCustomerDao.java b/dao/src/main/java/com/iluwatar/dao/InMemoryCustomerDao.java
index 947da23ca4a0..071db4f0b37d 100644
--- a/dao/src/main/java/com/iluwatar/dao/InMemoryCustomerDao.java
+++ b/dao/src/main/java/com/iluwatar/dao/InMemoryCustomerDao.java
@@ -43,7 +43,7 @@ public class InMemoryCustomerDao implements CustomerDao {
    */
   @Override
   public Stream<Customer> getAll() {
-    return idToCustomer.values().stream();
+    return idToCustomer.values().parallelStream();
   }
 
   @Override
diff --git a/eip-message-channel/src/main/java/com/iluwatar/eip/message/channel/App.java b/eip-message-channel/src/main/java/com/iluwatar/eip/message/channel/App.java
index d5929d0db3aa..50182af17b6b 100644
--- a/eip-message-channel/src/main/java/com/iluwatar/eip/message/channel/App.java
+++ b/eip-message-channel/src/main/java/com/iluwatar/eip/message/channel/App.java
@@ -70,7 +70,7 @@ public void configure() throws Exception {
     });
 
     context.start();
-    context.getRoutes().stream().forEach(r -> LOGGER.info(r.toString()));
+    context.getRoutes().parallelStream().forEach(r -> LOGGER.info(r.toString()));
     context.stop();
   }
 }
diff --git a/eip-publish-subscribe/src/main/java/com/iluwatar/eip/publish/subscribe/App.java b/eip-publish-subscribe/src/main/java/com/iluwatar/eip/publish/subscribe/App.java
index 7c7e77a1848a..90d1f8f40060 100644
--- a/eip-publish-subscribe/src/main/java/com/iluwatar/eip/publish/subscribe/App.java
+++ b/eip-publish-subscribe/src/main/java/com/iluwatar/eip/publish/subscribe/App.java
@@ -65,7 +65,7 @@ public void configure() throws Exception {
     });
     ProducerTemplate template = context.createProducerTemplate();
     context.start();
-    context.getRoutes().stream().forEach(r -> LOGGER.info(r.toString()));
+    context.getRoutes().parallelStream().forEach(r -> LOGGER.info(r.toString()));
     template.sendBody("direct:origin", "Hello from origin");
     context.stop();
   }
diff --git a/layers/src/main/java/com/iluwatar/layers/CakeInfo.java b/layers/src/main/java/com/iluwatar/layers/CakeInfo.java
index a1a2cb12eb9f..2c7fcdfc182d 100644
--- a/layers/src/main/java/com/iluwatar/layers/CakeInfo.java
+++ b/layers/src/main/java/com/iluwatar/layers/CakeInfo.java
@@ -59,7 +59,7 @@ public CakeInfo(CakeToppingInfo cakeToppingInfo, List<CakeLayerInfo> cakeLayerIn
    */
   public int calculateTotalCalories() {
     int total = cakeToppingInfo != null ? cakeToppingInfo.calories : 0;
-    total += cakeLayerInfos.stream().mapToInt(c -> c.calories).sum();
+    total += cakeLayerInfos.parallelStream().mapToInt(c -> c.calories).sum();
     return total;
   }
 
diff --git a/specification/src/main/java/com/iluwatar/specification/app/App.java b/specification/src/main/java/com/iluwatar/specification/app/App.java
index d4289f2d883f..93c94101714e 100644
--- a/specification/src/main/java/com/iluwatar/specification/app/App.java
+++ b/specification/src/main/java/com/iluwatar/specification/app/App.java
@@ -68,13 +68,13 @@ public static void main(String[] args) {
     // find all walking creatures
     LOGGER.info("Find all walking creatures");
     List<Creature> walkingCreatures =
-        creatures.stream().filter(new MovementSelector(Movement.WALKING))
+        creatures.parallelStream().filter(new MovementSelector(Movement.WALKING))
             .collect(Collectors.toList());
     walkingCreatures.stream().forEach(c -> LOGGER.info(c.toString()));
     // find all dark creatures
     LOGGER.info("Find all dark creatures");
     List<Creature> darkCreatures =
-        creatures.stream().filter(new ColorSelector(Color.DARK)).collect(Collectors.toList());
+        creatures.parallelStream().filter(new ColorSelector(Color.DARK)).collect(Collectors.toList());
     darkCreatures.stream().forEach(c -> LOGGER.info(c.toString()));
     // find all red and flying creatures
     LOGGER.info("Find all red and flying creatures");
diff --git a/thread-pool/src/test/java/com/iluwatar/threadpool/TaskTest.java b/thread-pool/src/test/java/com/iluwatar/threadpool/TaskTest.java
index 099cdc6e81be..f2686b8610b5 100644
--- a/thread-pool/src/test/java/com/iluwatar/threadpool/TaskTest.java
+++ b/thread-pool/src/test/java/com/iluwatar/threadpool/TaskTest.java
@@ -94,14 +94,15 @@ public void testIdGeneration() throws Exception {
       }
 
       final List<Integer> ids = service.invokeAll(tasks)
-          .stream()
+          .parallelStream()
           .map(TaskTest::get)
           .filter(Objects::nonNull)
           .collect(Collectors.toList());
 
       service.shutdownNow();
 
-      final long uniqueIdCount = ids.stream()
+      final long uniqueIdCount = ids.parallelStream()
+          .unordered()
           .distinct()
           .count();