* Throw an exception if a user could not be instatiated. * Add methods for adding, removing and retrieving users   with a given userId.
* Throw an exception if a user could not be instatiated.
* Add methods for adding, removing and retrieving users
  with a given userId.


git-svn-id: f6f45834fccde298d83fbef5743c9fd7982a26a3@39721 13f79535-47bb-0310-9956-ffa450edef68

apache/lenya,apache/lenya,apache/lenya,apache/lenya