Fair enough... So I did as suggested: copied my objects using jaxb to lib, which worked fine. This is however an unacceptable solution (as mentioned above), and the only purpose was to narrow down the problem. So back to start: any suggestions how to make jaxb work with classes loaded with the jbpm classloader? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4177636#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...