code: @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException {
      if (sessionSynchronization) {
        String syncKey = getSyncKey(request);
        synchronized (getSyncObject(syncKey)) {
          try {
            doService(request, response);
          }
          finally {
            removeSyncObject(syncKey);
          }
        }
      }
      else {
        doService(request, response);
      }
    }
docs: Processes all application requests, delegating them to their corresponding page, binary and JSON controllers.