The way is not smooth as I imagine before. I was imagine EJB 3 is easier then EJB 2. After trying some simple code for Stateles Bean and Entity Bean, then I try Stateful Bean. SLSB and Entity bean has no big deal to try, but when I try SLSB in the same environment, I got error.
I used java jdk 1.6 and JBoss 4.05. I just down load sample code of stateless, statefull and entity bean and try to deploy and run it. Stateless and entity bean is ok as I expected, but for stateful has a problem with class loader. Then i try to search by googling and I found this thread in forum of JBoss.
Then I changed my environment, switch to Tiger (jdk 5) again, and its work as I expected. Its also work in JBoss 4.0.4 and used jems.installer with ejb feature.
Welcome and go for the next step🙂