code: @Override
      public void reload(ResourceConfig configuration) {
          ApplicationHandler applicationHandler = new ApplicationHandler(configuration, null, locator);
          applicationHandlerDelegate = new DefaultApplicationHandlerDelegate(applicationHandler);
          getApplicationHandler().onReload(this);
          applicationHandler.onStartup(this);
      }
docs: Reload the hosted Jersey application using a new {@link ResourceConfig
  configuration}.
  
  @param configuration new configuration used for the reload.