code: public void setTemplate(String template) throws MissingIncludeException {
  	PageSource ps = pageContext.getCurrentPageSource().getRealPage(template);
  	if (!ps.exists()) throw new MissingIncludeException(ps);
  	errorPage.setTemplate(ps);
      }
docs: set the value template The relative path to the custom error page.
  
  @param template value to set
  @throws MissingIncludeException