diff --git a/src/main/java/com/datadoghq/trace/Writer.java b/src/main/java/com/datadoghq/trace/Writer.java
index 8bcba88b326..02714f234d2 100644
--- a/src/main/java/com/datadoghq/trace/Writer.java
+++ b/src/main/java/com/datadoghq/trace/Writer.java
@@ -1,8 +1,8 @@
 package com.datadoghq.trace;
 
-import java.util.List;
+import com.datadoghq.trace.impl.DDSpan;
 
-import io.opentracing.Span;
+import java.util.List;
 
 /**
  *	A writer is responsible to send collected spans to some place
@@ -14,7 +14,7 @@ public interface Writer {
      * 
      * @param trace the list of spans to write
      */
-    void write(List<Span> trace);
+    void write(List<DDSpan> trace);
 
     /**
      * Indicates to the writer that no future writing will come and it should terminates all connections and tasks
diff --git a/src/main/java/com/datadoghq/trace/impl/DDSpan.java b/src/main/java/com/datadoghq/trace/impl/DDSpan.java
index abb21b52be2..e3f8ff20f59 100644
--- a/src/main/java/com/datadoghq/trace/impl/DDSpan.java
+++ b/src/main/java/com/datadoghq/trace/impl/DDSpan.java
@@ -60,7 +60,7 @@ public void finish(long stopTimeMillis) {
         // warn if one of the parent's children is not finished
         if (this.isRootSpan()) {
             logger.debug(this + " - The current span is marked as a root span");
-            List<Span> spans = this.context.getTrace();
+            List<DDSpan> spans = this.context.getTrace();
             logger.debug(this + " - Checking " + spans.size() + " children attached to the current span");
 
             for (Span span : spans) {
diff --git a/src/main/java/com/datadoghq/trace/impl/DDSpanContext.java b/src/main/java/com/datadoghq/trace/impl/DDSpanContext.java
index 6025f1a4666..740b4c36946 100644
--- a/src/main/java/com/datadoghq/trace/impl/DDSpanContext.java
+++ b/src/main/java/com/datadoghq/trace/impl/DDSpanContext.java
@@ -23,7 +23,7 @@ public class DDSpanContext implements io.opentracing.SpanContext {
     private final boolean errorFlag;
     private final Map<String, Object> metrics;
     private final String spanType;
-    private final List<Span> trace;
+    private final List<DDSpan> trace;
     // Others attributes
     private boolean sampled;
     private DDTracer tracer;
@@ -40,7 +40,7 @@ public DDSpanContext(
             Map<String, Object> metrics,
             String spanType,
             boolean sampled,
-            List<Span> trace,
+            List<DDSpan> trace,
             DDTracer tracer) {
 
         this.traceId = traceId;
@@ -60,7 +60,7 @@ public DDSpanContext(
         this.sampled = sampled;
 
         if (trace == null) {
-            this.trace = new ArrayList<Span>();
+            this.trace = new ArrayList<DDSpan>();
         } else {
             this.trace = trace;
         }
@@ -137,7 +137,7 @@ public Iterable<Map.Entry<String, String>> baggageItems() {
     }
 
     @JsonIgnore
-    public List<Span> getTrace() {
+    public List<DDSpan> getTrace() {
         return this.trace;
     }
 
diff --git a/src/main/java/com/datadoghq/trace/impl/DDTracer.java b/src/main/java/com/datadoghq/trace/impl/DDTracer.java
index 7a0d16614b0..b871437c675 100644
--- a/src/main/java/com/datadoghq/trace/impl/DDTracer.java
+++ b/src/main/java/com/datadoghq/trace/impl/DDTracer.java
@@ -3,7 +3,6 @@
 import com.datadoghq.trace.Sampler;
 import com.datadoghq.trace.Writer;
 import com.datadoghq.trace.writer.impl.LoggingWritter;
-
 import io.opentracing.Span;
 import io.opentracing.SpanContext;
 import io.opentracing.propagation.Format;
@@ -43,9 +42,9 @@ public <C> SpanContext extract(Format<C> format, C c) {
         throw new UnsupportedOperationException();
     }
 
-    public void write(List<Span> trace) {
+    public void write(List<DDSpan> trace) {
         if (trace.size() == 0) return;
-        if (this.sampler.sample((DDSpan) trace.get(0))) {
+        if (this.sampler.sample(trace.get(0))) {
             this.writer.write(trace);
         }
     }
diff --git a/src/main/java/com/datadoghq/trace/writer/impl/DDAgentWriter.java b/src/main/java/com/datadoghq/trace/writer/impl/DDAgentWriter.java
index ff2ae1850a4..16b2bbd2fa9 100644
--- a/src/main/java/com/datadoghq/trace/writer/impl/DDAgentWriter.java
+++ b/src/main/java/com/datadoghq/trace/writer/impl/DDAgentWriter.java
@@ -1,18 +1,17 @@
 package com.datadoghq.trace.writer.impl;
 
+import com.datadoghq.trace.Writer;
+import com.datadoghq.trace.impl.DDSpan;
+import io.opentracing.Span;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.Semaphore;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import com.datadoghq.trace.Writer;
-
-import io.opentracing.Span;
-
 /**
  * This writer write provided traces to the a DD agent which is most of time located on the same host.
  * 
@@ -47,7 +46,7 @@ public class DDAgentWriter implements Writer {
 	/**
 	 * In memory collection of traces waiting for departure
 	 */
-	protected final BlockingQueue<List<Span>> traces;
+	protected final BlockingQueue<List<DDSpan>> traces;
 	
 	/**
 	 * Async worker that posts the spans to the DD agent
@@ -68,7 +67,7 @@ public DDAgentWriter(DDApi api) {
 		this.api = api;
 		
 		tokens = new Semaphore(DEFAULT_MAX_SPANS);
-		traces = new ArrayBlockingQueue<List<Span>>(DEFAULT_MAX_SPANS);
+		traces = new ArrayBlockingQueue<List<DDSpan>>(DEFAULT_MAX_SPANS);
 
 		asyncWriterThread = new Thread(new SpansSendingTask(), "dd.DDAgentWriter-SpansSendingTask");
 		asyncWriterThread.setDaemon(true);
@@ -78,7 +77,7 @@ public DDAgentWriter(DDApi api) {
 	/* (non-Javadoc)
 	 * @see com.datadoghq.trace.Writer#write(java.util.List)
 	 */
-	public void write(List<Span> trace) {
+	public void write(List<DDSpan> trace) {
 		//Try to add a new span in the queue
 		boolean proceed = tokens.tryAcquire(trace.size());
 
@@ -109,10 +108,10 @@ protected class SpansSendingTask implements Runnable {
 		public void run() {
 			while (true) {
 				try {
-					List<List<Span>> payload = new ArrayList<List<Span>>();
+					List<List<DDSpan>> payload = new ArrayList<List<DDSpan>>();
 					
 					//WAIT until a new span comes
-					List<Span> l = DDAgentWriter.this.traces.take();
+					List<DDSpan> l = DDAgentWriter.this.traces.take();
 					payload.add(l);
 					
 					//Drain all spans up to a certain batch suze
@@ -124,7 +123,7 @@ public void run() {
 
 					//Compute the number of spans sent
 					int spansCount = 0;
-					for(List<Span> trace:payload){
+					for(List<DDSpan> trace:payload){
 						spansCount+=trace.size();
 					}
 					logger.debug("Async writer just sent "+spansCount+" spans through "+payload.size()+" traces");
diff --git a/src/main/java/com/datadoghq/trace/writer/impl/DDApi.java b/src/main/java/com/datadoghq/trace/writer/impl/DDApi.java
index 58b1b08e349..dbccf4a336a 100644
--- a/src/main/java/com/datadoghq/trace/writer/impl/DDApi.java
+++ b/src/main/java/com/datadoghq/trace/writer/impl/DDApi.java
@@ -5,6 +5,7 @@
 import java.net.URL;
 import java.util.List;
 
+import com.datadoghq.trace.impl.DDSpan;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -53,7 +54,7 @@ public DDApi(String host, int port, SpanSerializer spanSerializer) {
      * @param traces the traces to be sent
      * @return the staus code returned
      */
-    public boolean sendTraces(List<List<Span>> traces) {
+    public boolean sendTraces(List<List<DDSpan>> traces) {
         String payload = null;
         try {
             payload = spanSerializer.serialize(traces);
diff --git a/src/main/java/com/datadoghq/trace/writer/impl/LoggingWritter.java b/src/main/java/com/datadoghq/trace/writer/impl/LoggingWritter.java
index be18100ed6f..9f4798d4a86 100644
--- a/src/main/java/com/datadoghq/trace/writer/impl/LoggingWritter.java
+++ b/src/main/java/com/datadoghq/trace/writer/impl/LoggingWritter.java
@@ -2,6 +2,7 @@
 
 import java.util.List;
 
+import com.datadoghq.trace.impl.DDSpan;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -14,7 +15,7 @@ public class LoggingWritter implements Writer{
 	protected static final Logger logger = LoggerFactory.getLogger(LoggingWritter.class.getName());
 	
 	@Override
-	public void write(List<Span> trace) {
+	public void write(List<DDSpan> trace) {
 		logger.info("write(trace): "+trace);
 	}
 
diff --git a/src/test/java/com/datadoghq/trace/impl/DDTracerTest.java b/src/test/java/com/datadoghq/trace/impl/DDTracerTest.java
index 123e9885c5b..9a5d947e492 100644
--- a/src/test/java/com/datadoghq/trace/impl/DDTracerTest.java
+++ b/src/test/java/com/datadoghq/trace/impl/DDTracerTest.java
@@ -29,7 +29,7 @@ public void write() throws Exception {
                 .thenReturn(true)
                 .thenReturn(false);
 
-        List<Span> spans = new ArrayList<Span>();
+        List<DDSpan> spans = new ArrayList<DDSpan>();
         spans.add(span);
         spans.add(span);
         spans.add(span);
diff --git a/src/test/java/com/datadoghq/trace/writer/impl/DDAgentWriterTest.java b/src/test/java/com/datadoghq/trace/writer/impl/DDAgentWriterTest.java
index e5b82bd3ece..8be0f388ea6 100644
--- a/src/test/java/com/datadoghq/trace/writer/impl/DDAgentWriterTest.java
+++ b/src/test/java/com/datadoghq/trace/writer/impl/DDAgentWriterTest.java
@@ -20,7 +20,7 @@ public class DDAgentWriterTest {
 
 	DDSpan parent = null;
 	DDApi mockedAPI = null;
-	List<List<Span>> traces = new ArrayList<List<Span>>();
+	List<List<DDSpan>> traces = new ArrayList<List<DDSpan>>();
 	DDAgentWriter ddAgentWriter = null;
 
 	@Before