diff --git a/core/src/main/scala/org/apache/spark/Accumulators.scala b/core/src/main/scala/org/apache/spark/Accumulators.scala
index fe1537a610ec53eb669790bc4757accb5d163e5b..df01b2e9421807e22912b56f48dc72a7ea47722f 100644
--- a/core/src/main/scala/org/apache/spark/Accumulators.scala
+++ b/core/src/main/scala/org/apache/spark/Accumulators.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark
 
-import java.io.ObjectInputStream
+import java.io.{ObjectInputStream, Serializable}
 
 import scala.collection.mutable.Map
 import scala.collection.generic.Growable
diff --git a/core/src/main/scala/org/apache/spark/broadcast/Broadcast.scala b/core/src/main/scala/org/apache/spark/broadcast/Broadcast.scala
index cf0904fc85aed00f04ab81eb16a11b77898f027e..d113d4040594d47fa4f188dfddfb5ba366360cf2 100644
--- a/core/src/main/scala/org/apache/spark/broadcast/Broadcast.scala
+++ b/core/src/main/scala/org/apache/spark/broadcast/Broadcast.scala
@@ -17,6 +17,7 @@
 
 package org.apache.spark.broadcast
 
+import java.io.Serializable
 import java.util.concurrent.atomic.AtomicLong
 
 import org.apache.spark._