I am using Jboss 4.0.5GA. It was working well until I got the following exception Caused by: org.hibernate.PropertyAccessException: IllegalArgumentException occurred calling getter of package.User.id It happens when I redeploy and run the same application(the same application I have redeployed many many times without any errors before). If I stop and re-start JBoss, the exception disappear. I am in development stage, it takes a long time to stop/start JBoss. Thanks for help! View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4026952#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...