I have same problem. If I can to list login of all users connected to a JBoss application, I can check and not allow the certain clients use the same account to login.(Ex: A use usename aaa, but If B use username aaa ---> he can't login!).
have some ideas ?
well you know. Basically username should be unique.
As for listing users. You can create a Stateless component to hold userlist and Use interceptor to update list and timestamp each time some action is rendered or page accesed.