1 files changed, 5 insertions, 5 deletions
diff --git a/core/src/main/scala/org/apache/spark/ContextCleaner.scala b/core/src/main/scala/org/apache/spark/ContextCleaner.scala
index 8fc657c5eb..76692ccec8 100644
--- a/core/src/main/scala/org/apache/spark/ContextCleaner.scala
+++ b/core/src/main/scala/org/apache/spark/ContextCleaner.scala
@@ -278,9 +278,9 @@ private object ContextCleaner {
  * Listener class used for testing when any item has been cleaned by the Cleaner class.
  */
 private[spark] trait CleanerListener {
-  def rddCleaned(rddId: Int)
-  def shuffleCleaned(shuffleId: Int)
-  def broadcastCleaned(broadcastId: Long)
-  def accumCleaned(accId: Long)
-  def checkpointCleaned(rddId: Long)
+  def rddCleaned(rddId: Int): Unit
+  def shuffleCleaned(shuffleId: Int): Unit
+  def broadcastCleaned(broadcastId: Long): Unit
+  def accumCleaned(accId: Long): Unit
+  def checkpointCleaned(rddId: Long): Unit
 }