Halo, I have gained some insight into the null children. SignalLog, TransitionLog and ActionLog all inherit from CompositeLog in the java class whilst the corresponding hibernate mapping file says | <subclass name="org.jbpm.graph.log.ActionLog" | extends="org.jbpm.logging.log.ProcessLog" | discriminator-value="A"> i.e. that ActionLog extends ProcessLog. If I change the hibernate mapping file to extends CompositeLog then the children are mapped and no longer null. Is this a feature or a bug?? Thanks Pieter View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4158137#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...