Dear All, I used below tools to build up my EJB project : - NetBean - JBoss - MySQL After successful created Stateless Bean & persistence units. I try to create Entity class from database. After that, I try to deploy such project and JBoss Application Server response below error message : ObjectName: persistence.units:ear=ScheduleTool.ear,jar=ScheduleTool-ejb.jar,unitName=ScheduleTool-ejbPU State: FAILED Reason: java.lang.IllegalStateException: Can't overwrite cause I Depend On: jboss.jca:service=DataSourceBinding,name=STS Also, I cannot find Persistence.Units item in Global JNDI Namespace webpage. Please please kindly been help. Thanks ! OUHK View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4185588#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...