diff --git a/core/src/main/scala/org/apache/spark/executor/ExecutorURLClassLoader.scala b/core/src/main/scala/org/apache/spark/executor/ExecutorURLClassLoader.scala
index f60e37ec814b6..208e77073fd03 100644
--- a/core/src/main/scala/org/apache/spark/executor/ExecutorURLClassLoader.scala
+++ b/core/src/main/scala/org/apache/spark/executor/ExecutorURLClassLoader.scala
@@ -32,7 +32,7 @@ private[spark] trait MutableURLClassLoader extends ClassLoader {
 }
 
 private[spark] class ChildExecutorURLClassLoader(urls: Array[URL], parent: ClassLoader)
-  extends ClassLoader with MutableURLClassLoader {
+  extends MutableURLClassLoader {
 
   private object userClassLoader extends URLClassLoader(urls, null){
     override def addURL(url: URL) {