"kukeltje" wrote : suppose xpdl or ebBP comes in... will that out 1 or 2 in favour of the other? (I cannot decide since it is not my field of expertise... If xpdl or ebXML came in they'd probably need to extend ProcessDefinition as well, by either aggregation or inheritance. Since the Node mapping already uses a discriminator, the obvious choice is taking the same path for ProcessDefinition. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4019548#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...