This issue provided by Jboss classloading specific. Log messages seems from MyFaces library - but this demo DON'T USE MYFACES, and war contain only Sun RI implementation ! As I thing, You have myfaces libraries loaded by other application or put it in server lib folder. See http://wiki.jboss.org/wiki/Wiki.jsp?page=ClassLoadingOverview and related pages for properly configuration. P.S. This sample run without problem on clean Jboss 4.04.GA installation. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3968339#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...