SessionUtils.validSessionVerification(request, mapping);
  public ActionForward execute(ActionMapping mapping, ActionForm form,                                HttpServletRequest request,                                HttpServletResponse response)      throws Exception {        HttpSession sessao = request.getSession(false);    if (sessao != null) {        /* Obtem o parametro do submit que indica a operacao a realizar */                if(request.getParameter("operation").equals("Editar Aula"))            return (mapping.findForward("Editar"));                else if (request.getParameter("operation").equals("Apagar Aula"))            return (mapping.findForward("Apagar"));        else if (request.getParameter("operation").equals("Voltar"))            return (mapping.findForward("Voltar"));		return (mapping.findForward("voltar"));    } else      throw new Exception();  // nao ocorre... pedido passa pelo filtro Autorizacao   }