The JIRA answer pretty much answers it. A class loaded twice in different class loaders will appear different to the VM. In your case what most likely happens is that your class loads Validator from your application library while the identity portlet loads it from MyFaces, thus causing the ClassCastException. Try to remove the JSF libs from your application. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4133523#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...