final ResourceResolver oldResolver = io.setRequestResourceResolver(resolver);
jspfh.incUsage();
try {
final JspServletWrapper errorJsp = getJspWrapper(scriptName, slingBindings);
errorJsp.service(slingBindings);
// The error page could be inside an include.
final SlingHttpServletRequest request = slingBindings.getRequest();
final Throwable t = (Throwable)request.getAttribute("javax.servlet.jsp.jspException");