code: private void restoreFromSession(IExtendedRequest extRequest, HttpServletRequest req, String reqURL) {
  		HttpSession postparamsession = req.getSession(false);
  		if (postparamsession == null) {
  			return;
  		}
  		String previousReq = (String) postparamsession.getAttribute(INITIAL_URL);
  		if (previousReq != null && previousReq.equals(reqURL)) {
  			try {
  				if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
  					Tr.debug(tc, "Found the session, restoring POST parameters.");
  				}
  				extRequest.setMethod("POST");
  				Map paramValues = (Map) postparamsession.getAttribute(PARAM_VALUES);
  
  				if (paramValues != null && !paramValues.isEmpty()) {
  					if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
  						Tr.debug(tc, "Restoring POST paramameters for URL : " + reqURL);
  					}
  					extRequest.setInputStreamData((HashMap) paramValues);
  				}
  			} catch (IOException exc) {
  				if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
  					Tr.debug(tc, "IOException restoring POST parameters onto a cookie: ", new Object[] { exc });
  				}
  			}
  		} else if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
  			Tr.debug(tc, "Parameters NOT restored. Original URL : " + previousReq + " req. URL : " + reqURL);
  		}
  
  		postparamsession.setAttribute(INITIAL_URL, null);
  		postparamsession.setAttribute(PARAM_NAMES, null);
  		postparamsession.setAttribute(PARAM_VALUES, null);
  	}
docs: Restore the POST parameters from session
  
  @param extRequest
  @param req
  @param reqURL