Spec compliancy :( It was a PITA for me as well.... merge() should work for a detached object though! View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3973251#3973251 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=3973251