diff --git a/src/java/org/apache/commons/collections/collection/CompositeCollection.java b/src/java/org/apache/commons/collections/collection/CompositeCollection.java
index 3add3edd2..3d38b2558 100644
--- a/src/java/org/apache/commons/collections/collection/CompositeCollection.java
+++ b/src/java/org/apache/commons/collections/collection/CompositeCollection.java
@@ -45,6 +45,9 @@ import org.apache.commons.collections.list.UnmodifiableList;
  */
 public class CompositeCollection<E> implements Collection<E>, Serializable {
 
+    /** Serialization version */
+    private static final long serialVersionUID = 1L;
+
     /** CollectionMutator to handle changes to the collection */
     protected CollectionMutator<E> mutator;
 
diff --git a/src/java/org/apache/commons/collections/set/CompositeSet.java b/src/java/org/apache/commons/collections/set/CompositeSet.java
index ca84d339c..b007599f2 100644
--- a/src/java/org/apache/commons/collections/set/CompositeSet.java
+++ b/src/java/org/apache/commons/collections/set/CompositeSet.java
@@ -37,6 +37,9 @@ import org.apache.commons.collections.collection.CompositeCollection;
  */
 public class CompositeSet<E> extends CompositeCollection<E> implements Set<E> {
 
+    /** Serialization version */
+    private static final long serialVersionUID = 1L;
+
     /**
      * Create an empty CompositeSet
      */
diff --git a/src/test/org/apache/commons/collections/map/EmptyMapMutator.java b/src/test/org/apache/commons/collections/map/EmptyMapMutator.java
index 296a810ce..63316320b 100644
--- a/src/test/org/apache/commons/collections/map/EmptyMapMutator.java
+++ b/src/test/org/apache/commons/collections/map/EmptyMapMutator.java
@@ -25,6 +25,9 @@ import java.util.Collection;
  * class also has to be serialized. 
  */
 class EmptyMapMutator implements CompositeMap.MapMutator {
+    /** Serialization version */
+    private static final long serialVersionUID = 1L;
+
     public void resolveCollision(CompositeMap composite,
     Map existing,
     Map added,
diff --git a/src/test/org/apache/commons/collections/set/EmptySetMutator.java b/src/test/org/apache/commons/collections/set/EmptySetMutator.java
index 1de97097a..d232dcf6e 100644
--- a/src/test/org/apache/commons/collections/set/EmptySetMutator.java
+++ b/src/test/org/apache/commons/collections/set/EmptySetMutator.java
@@ -28,6 +28,10 @@ import org.apache.commons.collections.collection.CompositeCollection;
  * class also has to be serialized. 
  */
 class EmptySetMutator<E> implements CompositeSet.SetMutator<E> {
+
+    /** Serialization version */
+    private static final long serialVersionUID = 1L;
+
     private Set<E> contained;
 
     public EmptySetMutator(Set<E> set) {