code: public void save(HttpServletRequest req, HttpServletResponse res, AuthenticationResult authResult, boolean keepInput) {
  		if (!req.getMethod().equalsIgnoreCase("POST")) {
  			return;
  		}
  
  		if (!(req instanceof IExtendedRequest)) {
  			if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
  				Tr.debug(tc, "It is not an IExtendedRequest object");
  			}
  			return;
  		}
  		restorePostParams((SRTServletRequest) req);
  
  		String reqURL = req.getRequestURI();
  		try {
  			String postParamSaveMethod = webAppSecurityConfig.getPostParamSaveMethod();
  			if (postParamSaveMethod.equalsIgnoreCase(WebAppSecurityConfig.POST_PARAM_SAVE_TO_COOKIE)) {
  				saveToCookie((IExtendedRequest) req, reqURL, authResult, keepInput);
  			} else if (postParamSaveMethod.equalsIgnoreCase(WebAppSecurityConfig.POST_PARAM_SAVE_TO_SESSION)) {
  				IExtendedRequest extRequest = (IExtendedRequest) req;
  				Map params = extRequest.getInputStreamData();
  				saveToSession(req, reqURL, params);
  			}
  		} catch (IOException exc) {
  			if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
  				Tr.debug(tc, "IO Exception storing POST parameters onto a cookie or session: ", new Object[] { exc });
  			}
  		}
  	}
docs: Save POST parameters to the cookie or session.
  
  @param req
  @param res
  @param authResult
  @param keepInput : preserve parameter buffer for further read operation. This is only valid for cookie.