Yep that's the point, I'm storing serialized classes :-( That would be a major problem when upgrading my program... View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4232143#4232143 Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&p=4232143