this link https://jira.jboss.org/jira/browse/JBWS-2649 says "The problem is simply that you can't mix the jbossws saaj implementation and the Sun's one. Please follow the installation instructions for using JDK6 (putting jbossws libraries in endorsed lib dir) and this exception should not happen." but in JBoss 5.1.0 GA for JDK 6 has already native-saaj links on endorsed lib dir View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4260327#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...