code: private void saveToSession(HttpServletRequest req, String reqURL, Map params) {
  		HttpSession postparamsession = req.getSession(true);
  		if (postparamsession != null && params != null && !params.isEmpty()) {
  			postparamsession.setAttribute(INITIAL_URL, reqURL);
  			postparamsession.setAttribute(PARAM_NAMES, null);
  			postparamsession.setAttribute(PARAM_VALUES, params);
  			if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
  				Tr.debug(tc, "URL saved: " + reqURL.toString());
  			}
  		}
  	}
docs: Save POST parameters (reqURL, parameters) to a session
  
  @param req
  @param reqURL
  @param params