code: public static void init(final String _appKey,
                              final Set<UUID> _loginRoles)
      {
          if (AppAccessHandler.HANDLER == null) {
              AppAccessHandler.HANDLER = new AppAccessHandler(_appKey, _loginRoles);
          }
      }
docs: Init the Handler. Can only be executed once.
  @param _appKey of the application
  @param _loginRoles allowd Login roles