Fix potential NPE
diff --git a/commons-jcs-core/src/main/java/org/apache/commons/jcs/engine/control/CompositeCacheManager.java b/commons-jcs-core/src/main/java/org/apache/commons/jcs/engine/control/CompositeCacheManager.java
index 7f50bcb..1d29b56 100644
--- a/commons-jcs-core/src/main/java/org/apache/commons/jcs/engine/control/CompositeCacheManager.java
+++ b/commons-jcs-core/src/main/java/org/apache/commons/jcs/engine/control/CompositeCacheManager.java
@@ -591,7 +591,10 @@
         synchronized (CompositeCacheManager.class)
         {
             // shutdown element event queue
-            this.elementEventQueue.dispose();
+            if (this.elementEventQueue != null)
+            {
+                this.elementEventQueue.dispose();
+            }
 
             // shutdown all scheduled jobs
             this.scheduledExecutor.shutdownNow();