code: public void pushParameterStack()
      {
          if (TraceComponent.isAnyTracingEnabled()&&logger.isLoggable (Level.FINE)){  //306998.15
              logger.logp(Level.FINE, CLASS_NAME,"pushParameterStack", "entry");
          }
          if (WCCustomProperties.CHECK_REQUEST_OBJECT_IN_USE){
              checkRequestObjectInUse();
          }
          SRTServletRequestThreadData reqData = SRTServletRequestThreadData.getInstance();
          if (reqData.getParameters() == null)
          {
              reqData.pushParameterStack(null);
          } else
          {
              _paramStack.push(((Hashtable) reqData.getParameters()).clone());
          }
          if (TraceComponent.isAnyTracingEnabled()&&logger.isLoggable (Level.FINE) && reqData.getParameters() !=null)  //306998.15
          {
              debugParams(reqData.getParameters());
          }
      }
docs: Save the state of the parameters before a call to include or forward.