diff --git a/core/src/main/scala/org/apache/spark/deploy/master/PersistenceEngine.scala b/core/src/main/scala/org/apache/spark/deploy/master/PersistenceEngine.scala
index da5060778edeb8028054f5bd29346e6646229995..a03d460509e037901cf6adf3b1d06b9b2e2233e8 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/PersistenceEngine.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/PersistenceEngine.scala
@@ -33,7 +33,7 @@ import scala.reflect.ClassTag
  * The implementation of this trait defines how name-object pairs are stored or retrieved.
  */
 @DeveloperApi
-trait PersistenceEngine {
+abstract class PersistenceEngine {
 
   /**
    * Defines how the object is serialized and persisted. Implementation will