code: protected void startServingWebServer() {
      stopRejectingWebServer();
      mWebServer =
          new MasterWebServer(ServiceType.MASTER_WEB.getServiceName(), mWebBindAddress, this);
      // reset master web port
      // Add the metrics servlet to the web server.
      mWebServer.addHandler(mMetricsServlet.getHandler());
      // Add the prometheus metrics servlet to the web server.
      mWebServer.addHandler(mPMetricsServlet.getHandler());
      // start web ui
      mWebServer.start();
    }
docs: Starts serving web ui server, resetting master web port, adding the metrics servlet to the web
  server and starting web ui.