More details please. Please post the entire exception stacktrace and also let us know where that class is located (which jar which ear). Have you configured classloader isolation for the EARs through jboss-app.xml? While posting logs or xml content or code, please remember to wrap it in a code block by using the Code button in the message editor window. Please use the Preview button to ensure that your post is correctly formatted. P.S: For JBossAS5 we have a dedicated forum here http://www.jboss.com/index.html?module=bb&op=viewforum&f=287 View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4200893#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...