Thanks so much. Indeed it worked after I changed the Mixin method to take MyPojo as an input argument. I was wonder why this has to be the case though. I can not see from the AOP document that the mixin creation method has to take the opriginal pojo as the argument. * be public * be static * contain the logic to create the mixin class * return an instance of the mixin class Perhaps they should add one more requirement or someone can explain why this is the case? Thanks. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3990785#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...