code: protected void notFound(HttpServletResponse response) {
  
          try {
              response.sendError(HttpServletResponse.SC_NOT_FOUND);
          } catch (IllegalStateException e) {
              ;
          } catch (IOException e) {
              ;
          }
  
      }
docs: Report a "not found" error for the specified resource.  FIXME:  We
  should really be using the error reporting settings for this web
  application, but currently that code runs at the wrapper level rather
  than the context level.
  
  @param response The response we are creating