code: private boolean handleException( Throwable th,
                                       FlowController fc,
                                       HttpServletRequest request,
                                       HttpServletResponse response )
      {
          try
          {
              ActionMapping mapping = InternalUtils.getCurrentActionMapping( request );
              ActionForm form = InternalUtils.getCurrentActionForm( request );
              ActionForward fwd = fc.handleException( th, mapping, form, request, response );
              fc.getRequestProcessor().doActionForward( request, response, fwd );
              return true;
          }
          catch ( Throwable t )
          {
              LOG.error("Exception occurred while handling exception " + th.getClass().getName()
                  + ".  The original exception will be thrown.  Cause: " + t, t);
              return false;
          }
      }
docs: Internal method that implements exception handling functionality for exceptions thrown while
  rendering pages (JSPs, etc) associated with a Page Flow.
  
  @param th the original throwable
  @param fc the flow control associated with this request
  @param request the request
  @param response the response
  @return <code>true</code> if the page flow handled the request; <code>false</code> if another exception
  occurred while handling this one.