throw new NotAuthorizedException();
throw new NotAuthorizedActionException("error.NotAuthorized");
    public final ActionForward execute(ActionMapping mapping, ActionForm form,            HttpServletRequest request, HttpServletResponse response) throws Exception {        // check hosts accessing this action        if (! HostAccessControl.isAllowed(this, request)) {            throw new NotAuthorizedException();        }                if (request.getMethod().equalsIgnoreCase("post")) {            final String username = request.getParameter("username");            final String password = request.getParameter("password");            final String requestURL = request.getRequestURL().toString();            final Object authenticationArgs[] = { username, password, requestURL, BaseAuthenticationAction.getRemoteHostName(request) };            String result = null;            try {                ServiceManagerServiceFactory.executeService(null, "KerberosExternalAuthentication",                        authenticationArgs);                result = SUCCESS_MESSAGE;            } catch (PasswordExpiredServiceException e) {                result = e.getMessage();            } catch (InvalidPasswordServiceException e) {                result = e.getMessage();            } catch (ExcepcaoAutenticacao e) {                result = KerberosException.WRONG_PASSWORD;            } catch (Exception e) {                result = UNEXPECTED_ERROR_MESSAGE;            }            response.setContentType("text/html");            response.getOutputStream().write(result.getBytes());        }        return null;    }