diff --git a/src/share/classes/java/util/JumboEnumSet.java b/src/share/classes/java/util/JumboEnumSet.java
index ccd8f901978cc73a046d7575035ee5c8d96a99d6..398836a1c3be9c8a3c8a836c63cb8324931c6cd8 100644
--- a/src/share/classes/java/util/JumboEnumSet.java
+++ b/src/share/classes/java/util/JumboEnumSet.java
@@ -34,6 +34,8 @@ package java.util;
  * @serial exclude
  */
 class JumboEnumSet<E extends Enum<E>> extends EnumSet<E> {
+    private static final long serialVersionUID = 334349849919042784L;
+
     /**
      * Bit vector representation of this set.  The ith bit of the jth
      * element of this array represents the  presence of universe[64*j +i]
diff --git a/src/share/classes/java/util/RegularEnumSet.java b/src/share/classes/java/util/RegularEnumSet.java
index 9615e7ea157d3cbb38fd77ec95252cad2ba62a22..a549fae2de1d506157824e5f0f1d28dd33341071 100644
--- a/src/share/classes/java/util/RegularEnumSet.java
+++ b/src/share/classes/java/util/RegularEnumSet.java
@@ -34,6 +34,7 @@ package java.util;
  * @serial exclude
  */
 class RegularEnumSet<E extends Enum<E>> extends EnumSet<E> {
+    private static final long serialVersionUID = 3411599620347842686L;
     /**
      * Bit vector representation of this set.  The 2^k bit indicates the
      * presence of universe[k] in this set.