Got it! You pointed the right thing! Thank you very much... A lot of the problems I've tried to solve these last days where caused by all that persistence thing. Now I think I've got it all clear. Therefore I packaged my DAO AND my class query in a datamodel.jar file with the persistence.xml in the META-INF. All my other classes are packaged in a services.jar file and it's aaaaaaaaall good! This sort of thing may be very obvious to some people but it wasn't at all to me so thanks again! I offer you my eternal gratitude! View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4153961#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...