"adrian(a)jboss.org" wrote : There's no way to check whether a collections is modifiable or otherwise. | True. You could address the scenario by catching the UnsupportedOperationException on Collection.add() and falling back to a default mechanism. It's not a complete solution but depending on how common you think the use case is, would address it without extra burden of configuration on user's part. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4060476#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...