HttpServletResponse res = (HttpServletResponse) response;
WebApp webApp = (WebApp) getServletContext();
FormLogin login = getFormLogin(webApp.getLogin());
Principal user = login.login(req, res, true);
if (log.isLoggable(Level.FINE))
log.fine(this + " login " + user + " using " + login);
if (res.isCommitted())