diff --git a/htrace-core/pom.xml b/htrace-core4/pom.xml
similarity index 99%
rename from htrace-core/pom.xml
rename to htrace-core4/pom.xml
index 81f2f87..b5d3c74 100644
--- a/htrace-core/pom.xml
+++ b/htrace-core4/pom.xml
@@ -22,7 +22,7 @@
     <relativePath>..</relativePath>
   </parent>
 
-  <name>htrace-core</name>
+  <name>htrace-core4</name>
   <url>http://incubator.apache.org/projects/htrace.html</url>
 
   <properties>
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/AlwaysSampler.java b/htrace-core4/src/main/java/org/apache/htrace/core/AlwaysSampler.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/AlwaysSampler.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/AlwaysSampler.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/CountSampler.java b/htrace-core4/src/main/java/org/apache/htrace/core/CountSampler.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/CountSampler.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/CountSampler.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/HTraceConfiguration.java b/htrace-core4/src/main/java/org/apache/htrace/core/HTraceConfiguration.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/HTraceConfiguration.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/HTraceConfiguration.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/LocalFileSpanReceiver.java b/htrace-core4/src/main/java/org/apache/htrace/core/LocalFileSpanReceiver.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/LocalFileSpanReceiver.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/LocalFileSpanReceiver.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/MilliSpan.java b/htrace-core4/src/main/java/org/apache/htrace/core/MilliSpan.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/MilliSpan.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/MilliSpan.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/NeverSampler.java b/htrace-core4/src/main/java/org/apache/htrace/core/NeverSampler.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/NeverSampler.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/NeverSampler.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/NullScope.java b/htrace-core4/src/main/java/org/apache/htrace/core/NullScope.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/NullScope.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/NullScope.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/POJOSpanReceiver.java b/htrace-core4/src/main/java/org/apache/htrace/core/POJOSpanReceiver.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/POJOSpanReceiver.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/POJOSpanReceiver.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/ProbabilitySampler.java b/htrace-core4/src/main/java/org/apache/htrace/core/ProbabilitySampler.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/ProbabilitySampler.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/ProbabilitySampler.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/Sampler.java b/htrace-core4/src/main/java/org/apache/htrace/core/Sampler.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/Sampler.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/Sampler.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/Span.java b/htrace-core4/src/main/java/org/apache/htrace/core/Span.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/Span.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/Span.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/SpanId.java b/htrace-core4/src/main/java/org/apache/htrace/core/SpanId.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/SpanId.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/SpanId.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/SpanReceiver.java b/htrace-core4/src/main/java/org/apache/htrace/core/SpanReceiver.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/SpanReceiver.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/SpanReceiver.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/StandardOutSpanReceiver.java b/htrace-core4/src/main/java/org/apache/htrace/core/StandardOutSpanReceiver.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/StandardOutSpanReceiver.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/StandardOutSpanReceiver.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/TimelineAnnotation.java b/htrace-core4/src/main/java/org/apache/htrace/core/TimelineAnnotation.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/TimelineAnnotation.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/TimelineAnnotation.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/TraceCallable.java b/htrace-core4/src/main/java/org/apache/htrace/core/TraceCallable.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/TraceCallable.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/TraceCallable.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/TraceExecutorService.java b/htrace-core4/src/main/java/org/apache/htrace/core/TraceExecutorService.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/TraceExecutorService.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/TraceExecutorService.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/TraceRunnable.java b/htrace-core4/src/main/java/org/apache/htrace/core/TraceRunnable.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/TraceRunnable.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/TraceRunnable.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/TraceScope.java b/htrace-core4/src/main/java/org/apache/htrace/core/TraceScope.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/TraceScope.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/TraceScope.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/Tracer.java b/htrace-core4/src/main/java/org/apache/htrace/core/Tracer.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/Tracer.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/Tracer.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/TracerId.java b/htrace-core4/src/main/java/org/apache/htrace/core/TracerId.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/TracerId.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/TracerId.java
diff --git a/htrace-core/src/main/java/org/apache/htrace/core/TracerPool.java b/htrace-core4/src/main/java/org/apache/htrace/core/TracerPool.java
similarity index 100%
rename from htrace-core/src/main/java/org/apache/htrace/core/TracerPool.java
rename to htrace-core4/src/main/java/org/apache/htrace/core/TracerPool.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestBadClient.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestBadClient.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestBadClient.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestBadClient.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestCountSampler.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestCountSampler.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestCountSampler.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestCountSampler.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestHTrace.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestHTrace.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestHTrace.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestHTrace.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestHTraceConfiguration.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestHTraceConfiguration.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestHTraceConfiguration.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestHTraceConfiguration.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestLocalFileSpanReceiver.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestLocalFileSpanReceiver.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestLocalFileSpanReceiver.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestLocalFileSpanReceiver.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestMilliSpan.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestMilliSpan.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestMilliSpan.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestMilliSpan.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestNullScope.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestNullScope.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestNullScope.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestNullScope.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestSampler.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestSampler.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestSampler.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestSampler.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestSpanId.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestSpanId.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestSpanId.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestSpanId.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestSpanReceiverBuilder.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestSpanReceiverBuilder.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestSpanReceiverBuilder.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestSpanReceiverBuilder.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TestTracerId.java b/htrace-core4/src/test/java/org/apache/htrace/core/TestTracerId.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TestTracerId.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TestTracerId.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TraceCreator.java b/htrace-core4/src/test/java/org/apache/htrace/core/TraceCreator.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TraceCreator.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TraceCreator.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/core/TraceGraph.java b/htrace-core4/src/test/java/org/apache/htrace/core/TraceGraph.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/core/TraceGraph.java
rename to htrace-core4/src/test/java/org/apache/htrace/core/TraceGraph.java
diff --git a/htrace-core/src/test/java/org/apache/htrace/util/TestUtil.java b/htrace-core4/src/test/java/org/apache/htrace/util/TestUtil.java
similarity index 100%
rename from htrace-core/src/test/java/org/apache/htrace/util/TestUtil.java
rename to htrace-core4/src/test/java/org/apache/htrace/util/TestUtil.java
diff --git a/pom.xml b/pom.xml
index 0e0342f..42e19ca 100644
--- a/pom.xml
+++ b/pom.xml
@@ -29,7 +29,7 @@
 
   <modules>
     <module>htrace-c</module>
-    <module>htrace-core</module>
+    <module>htrace-core4</module>
     <module>htrace-webapp</module>
     <module>htrace-zipkin</module>
     <module>htrace-hbase</module>