code:     public void removeUser(String username) {
  
          UserDatabase database = (UserDatabase) this.resource;
          User user = database.findUser(username);
          if (user == null) {
              return;
          }
          try {
              MBeanUtils.destroyMBean(user);
              database.removeUser(user);
          } catch (Exception e) {
              IllegalArgumentException iae = new IllegalArgumentException
                  ("Exception destroying user " + user + " MBean");
              iae.initCause(e);
              throw iae;
          }
  
      }
  
  
  