diff --git a/openjpa-kernel/src/main/java/org/apache/openjpa/enhance/PCRegistry.java b/openjpa-kernel/src/main/java/org/apache/openjpa/enhance/PCRegistry.java
index d64fc8055..8493ded74 100644
--- a/openjpa-kernel/src/main/java/org/apache/openjpa/enhance/PCRegistry.java
+++ b/openjpa-kernel/src/main/java/org/apache/openjpa/enhance/PCRegistry.java
@@ -26,6 +26,7 @@ import java.util.Map;
 import org.apache.openjpa.lib.util.Localizer;
 import org.apache.openjpa.lib.util.ReferenceMap;
 import org.apache.openjpa.lib.util.concurrent.ConcurrentReferenceHashMap;
+import org.apache.openjpa.lib.util.concurrent.ConcurrentReferenceHashSet;
 import org.apache.openjpa.util.UserException;
 
 /**
@@ -44,7 +45,9 @@ public class PCRegistry {
             ReferenceMap.HARD);
 
     // register class listeners
-    private static final Collection<RegisterClassListener> _listeners = new LinkedList<RegisterClassListener>();
+    // Weak reference prevents OutOfMemeoryError as described in OPENJPA-2042
+    private static final Collection<RegisterClassListener> _listeners = 
+            new ConcurrentReferenceHashSet<RegisterClassListener>(ConcurrentReferenceHashSet.WEAK);
 
     /**
      * Register a {@link RegisterClassListener}.
@@ -201,8 +204,11 @@ public class PCRegistry {
             _metas.put(pcClass, meta);
         }
         synchronized (_listeners) {
-            for (RegisterClassListener r : _listeners)
-                r.register(pcClass);
+            for (RegisterClassListener r : _listeners) {
+                if (r != null) {
+                    r.register(pcClass);
+                }
+            }
         }
     }