Problem solved I had a rubbish mapping, my bad. The mapping was incomplete: @ManyToOne | @JoinColumn(name = "A_FK") | public int getA(){ | return a; | } | public void setA(int a){ | this.a=a; | } The problem is that I got a nullpointer , when I tried to deploy to an old installation (4.0.4) I got a real errror msg : org.hibernate.AnnotationException: @OneToOne or @ManyToOne on entityB.a references an unknown entity: int | ThIS msg was understandably and it was a easy fix............. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3998979#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...