Index: common/common-util/src/main/java/com/sun/enterprise/loader/ASURLClassLoader.java
===================================================================
--- common/common-util/src/main/java/com/sun/enterprise/loader/ASURLClassLoader.java	(revision 39992)
+++ common/common-util/src/main/java/com/sun/enterprise/loader/ASURLClassLoader.java	(working copy)
@@ -563,7 +563,8 @@
             _logger.log(Level.WARNING,
                         "loader.asurlclassloader_done_already_called",
                         new Object[] { name, doneSnapshot });
-            return null;
+            // return an empty enumeration instead of null. See issue #13096
+            return Collections.enumeration(Collections.EMPTY_LIST);
         }
         List<URL> resourcesList = new ArrayList<URL>();