Hi, Is it possible to use Interfaces for OneToOne relations? For example (Pseudocode): | Entity A implements MarkerInterface {} | Entity B implements MarkerInterface {} | Entity C { | MarkerInterface something; | } | I know that its possible to use Inheritance, but im unable to use the same BaseClass in A and B. I just want to avoid this: | Entity class C { | A a; | B b; | } | Where its only allowed to set a or b instead. thx for your help, Bernhard View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3971009#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...