return username==null ? true:false;
return (tmpuser==null) ? true:false;
  private final boolean checkUsername(Admin admin, String username)    throws ServletException  {    if (username != null) username = username.trim();    if (username == null || username.length() == 0) {      throw new ServletException("Username must not be empty.");    }    UserAdminData tmpuser = null;    try {        tmpuser = adminsession.findUser(admin, username);     } catch (Exception e) {        throw new ServletException("Error checking username '" + username +": ", e);     }    return username==null ? true:false;  }