I guess Alexey nailed it. Anyway it's unlikely we'd ever turn on validation due to perf. reasons. My analysis of handing this kind of situation (two very similar but not identical namespaces with JBossXB or JAXB in general) came to the conclusion that you can't really do it cleanly without having completely separate object models, which of course is a ton of redundancy. Maybe there's some way you can hack it into telling you what namespace was parsed? Setting it as a property on your root element or something? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4261874#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...