Thank you Peter, you give me some instructions! But I don't think my classpath error! In my windows platform, Jboss 4.2.2 runs OK! But Jboss 4.2.3 and Jboss 5.0.* runs error! Follow your instruction, I add option -verbose:gc to JAVA_OPTS in run.bat, and I find following information in server.log: sun.boot.class.path=D:\jboss\lib\endorsed\activation.jar;D:\jboss\lib\endorsed\jaxb-api.jar;D:\jboss\lib\endorsed\jbossws-native-jaxws-ext.jar;D:\jboss\lib\endorsed\jbossws-native-jaxws.jar;D:\jboss\lib\endorsed\jbossws-native-saaj.jar;D:\jboss\lib\endorsed\resolver.jar;D:\jboss\lib\endorsed\serializer.jar;D:\jboss\lib\endorsed\stax-api.jar;D:\jboss\lib\endorsed\xalan.jar;D:\jboss\lib\endorsed\xercesImpl.jar;C:\Program Files\Java\jdk1.6.0_04\jre\lib\resources.jar;C:\Program Files\Java\jdk1.6.0_04\jre\lib\rt.jar;C:\Program Files\Java\jdk1.6.0_04\jre\lib\sunrsasign.jar;C:\Program Files\Java\jdk1.6.0_04\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.6.0_04\jre\lib\jce.jar;C:\Program Files\Java\jdk1.6.0_04\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.6.0_04\jre\classes I think all is OK! Can you find sth wrong! Peter? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4231463#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...