This is a classpath issue. I had this problem too trying to run a WS client from Eclipse. It took me a while, but in Eclipse, I did the following: - Add * ONLY * the xercesImpl.jar from the server lib/endorsed directory to your build path (DO NOT ADD resolver.jar or any of the other jars from here) - Add all jars in the server/client directory to your classpath - Add the stax-api.jar from the server/default/deploy/jboss.sar directory This solved the problem for me. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4147247#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...