Unfortunately, if using standard JBoss and Hibernate (no EJB3), the use of javassist is forced in the Hibernate MBean (createService() method of org.jboss.hibernate.jmx.Hibernate by hardcoding the property. To work around this I patched two classes: 1. Hibernate.java (remove createService() method or change the System.setProperty(..) line from javassist to cglib) 2. HibernateMBean (no changes, needed because Hibernate.java implements it). I don't know if there is an easier way to solve this, but at least it works. I can now send lazy Hibernate pojos (containing proxies) to the client without exceptions crashing down on me... htah View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3962474#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...