Page caching by overriding the getOutputStream() and getWriter() methods.

In your Action, you can just return null instead of an ActionForward

    public ActionForward perform(ActionMapping mapping,
                 ActionForm form,
                 HttpServletRequest request,
                 HttpServletResponse response)
    throws IOException, ServletException {
        response.setContentType("text/plain");
        response.getWriter().print("Hello World");
        return (null);
    };