code: private void scheduleUpdateFactory(final ServerControllerFactory controllerFactory) {
  		// change configuration using new (or null when not available) ServerControllerFactory
  		Future<?> future = configExecutor.submit(() -> updateController(config, controllerFactory));
  
  		// Make sure we destroy things synchronously
  		if (controllerFactory == null) {
  			try {
  				future.get(20, TimeUnit.SECONDS);
  				// CHECKSTYLE:OFF
  			} catch (Exception e) {
  				LOG.info("Error when updating factory: " + e.getMessage(), e);
  			}
  			// CHECKSTYLE:ON
  		}
  	}
docs: Called by tracker of {@link ServerControllerFactory} services
  @param controllerFactory