I resolved the problem! I Javaassist that is depended by Seam-IOC (using Maven), has conflict with JavaAssist in the Jboss Server. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4101588#4101588 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4101588