Index: src/java/org/datanucleus/state/JDOStateManagerImpl.java
===================================================================
--- src/java/org/datanucleus/state/JDOStateManagerImpl.java	(revision 2063)
+++ src/java/org/datanucleus/state/JDOStateManagerImpl.java	(working copy)
@@ -362,7 +362,7 @@
             pcCopy.jdoCopyFields(myPC, getAllFieldNumbers());
 
             // Swap the managed PC to be the copy and not the input
-            pcCopy.jdoReplaceStateManager(this);
+            replaceStateManager(pcCopy, this);
             myPC = pcCopy;
             disconnectClone((PersistenceCapable)pc);
         }
@@ -548,7 +548,7 @@
         this.myLC = myOM.getOMFContext().getApiAdapter().getLifeCycleState(LifeCycleState.DETACHED_CLEAN);
 
         this.myPC.jdoReplaceFlags();
-        myPC.jdoReplaceStateManager(this);
+        replaceStateManager(this);
     }
 
     /**
@@ -565,7 +565,7 @@
         {
             loadedFields[i] = true;
         }
-        myPC.jdoReplaceStateManager(this);
+        replaceStateManager(this);
     }
 
     /**
@@ -685,7 +685,7 @@
             new CachePopulateFieldManager(this, getSecondClassMutableFields(), myFP, state, cachedPC));
 
         // Disconnect the StateManager
-        ((PersistenceCapable)cachePC).jdoReplaceStateManager(null);
+        replaceStateManager(((PersistenceCapable)cachePC), null);
 
         return cachePC;
     }
@@ -897,8 +897,8 @@
         }
 
         // Swap the StateManager on the objects
-        pc.jdoReplaceStateManager(this);
-        myPC.jdoReplaceStateManager(null);
+        replaceStateManager(pc, this);
+        replaceStateManager(null);
 
         // Swap our object
         myPC = pc;
@@ -924,11 +924,11 @@
         }
 
         // Assign the new object to this StateManager temporarily so that we can copy its fields
-        pc.jdoReplaceStateManager(this);
+        replaceStateManager(pc, this);
         myPC.jdoCopyFields(pc, fieldNumbers);
 
         // Remove the StateManager from the other object
-        pc.jdoReplaceStateManager(null);
+        replaceStateManager(pc, null);
 
         // Set the loaded flags now that we have copied
         for (int i=0;i<fieldNumbers.length;i++)
@@ -945,7 +945,7 @@
     {
         try
         {
-            myPC.jdoReplaceStateManager(sm);
+            replaceStateManager(myPC, sm);
         }
         catch (SecurityException e)
         {
@@ -954,6 +954,30 @@
     }
 
     /**
+     * Utility to update some object to use a different state manager.
+     * @param pc Some object.
+     * @param sm The new state manager.
+     **/
+    private void replaceStateManager(final PersistenceCapable pc, final StateManager sm)
+    {
+        try
+        {
+            AccessController.doPrivileged( 
+                new PrivilegedAction () { 
+                    public Object run () { 
+                        pc.jdoReplaceStateManager(sm); 
+                        return null; 
+                    } 
+                } 
+            ); 
+        }
+        catch (SecurityException e)
+        {
+            throw new JDOFatalUserException(LOCALISER.msg("026000"), e);
+        }
+    }
+
+    /**
      * Method to enlist the managed object in the current transaction.
      */
     public void enlistInTransaction()
@@ -3611,7 +3635,7 @@
                 }
 
                 // Remove its StateManager since now detached or transient
-                detachedPC.jdoReplaceStateManager(null);
+                replaceStateManager(detachedPC, null);
             }
             catch (Exception e)
             {
@@ -3730,7 +3754,7 @@
             getCallbackHandler().preAttach(myPC);
 
             // Retrieve the updated values from the detached object
-            myPC.jdoReplaceStateManager(this);
+            replaceStateManager(this);
             retrieveDetachState(this);
 
             if (!persistent)
@@ -3862,7 +3886,7 @@
                 smDetachedPC.myVersion, true);
 
             // Remove the state manager from the detached PC
-            detachedPC.jdoReplaceStateManager(null);
+            replaceStateManager(detachedPC, null);
 
             // Remove the corss-referencing now we have finished the attach process
             smDetachedPC.referencedPC = null;
@@ -4645,7 +4669,7 @@
             // Reset jdoFlags in the clone to PersistenceCapable.READ_WRITE_OK 
             // and clear its state manager.
             pc.jdoReplaceFlags();
-            pc.jdoReplaceStateManager(null);
+            replaceStateManager(pc, null);
             return true;
         }
         else
@@ -4939,4 +4963,4 @@
                 return "???";
         }
     }
-}
\ No newline at end of file
+}
Index: src/java/org/datanucleus/metadata/MetaDataManager.java
===================================================================
--- src/java/org/datanucleus/metadata/MetaDataManager.java	(revision 2063)
+++ src/java/org/datanucleus/metadata/MetaDataManager.java	(working copy)
@@ -22,6 +22,8 @@
 import java.lang.reflect.Constructor;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -831,7 +833,7 @@
      * @param clr the ClassLoaderResolver
      * @return The ClassMetaData for this class (or null if not found)
      */
-    public synchronized AbstractClassMetaData getMetaDataForClass(Class c, ClassLoaderResolver clr)
+    public synchronized AbstractClassMetaData getMetaDataForClass(final Class c, final ClassLoaderResolver clr)
     {
         if (c == null)
         {
@@ -842,7 +844,10 @@
         {
             return null;
         }
-
+        AbstractClassMetaData ret = (AbstractClassMetaData)
+            AccessController.doPrivileged(
+                new PrivilegedAction () {
+                    public Object run () { 
         AbstractClassMetaData cmd = null;
         if (c.isInterface())
         {
@@ -889,6 +894,10 @@
         }
         utilisedFileMetaData.clear();
         return cmd;
+                    }
+                }
+            ); 
+        return ret;
     }
 
     /**