Hi Andreas, from looking at your base entity, i can see that you are mixing the levels of your annotations. In my experience this is a cause of so many problems (and if it causes any exceptions they are not very helpful at all), try moving all you annotations to field level or to method (getter) level. Let me know if this helps. Cheers, Andy View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4025016#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...