Continue:

Continue:
- updateUserData() was throwing an unchecked EJBException, now better the
  well-known UserNotFoundException (maybe subject for renaming?)
- re-added other business methods for checking of user existence. Please do NOT
  invoke them from your web/Swing application as this causes a lot EJB remote
  method invocations.
- Instead you should implement a similar method in your application and have the
  user list cached and checked against that cached list.

Signed-off-by: Roland Häder <roland@mxchange.org>