code: public static <T extends RestfulGateway> Optional<StaticFileServerHandler<T>> tryLoadWebContent(
  			GatewayRetriever<? extends T> leaderRetriever,
  			Time timeout,
  			File tmpDir) throws IOException {
  
  		if (isFlinkRuntimeWebInClassPath()) {
  			return Optional.of(new StaticFileServerHandler<>(
  				leaderRetriever,
  				timeout,
  				tmpDir));
  		} else {
  			return Optional.empty();
  		}
  	}
docs: Checks whether the flink-runtime-web dependency is available and if so returns a
  StaticFileServerHandler which can serve the static file contents.
  
  @param leaderRetriever to be used by the StaticFileServerHandler
  @param timeout for lookup requests
  @param tmpDir to be used by the StaticFileServerHandler to store temporary files
  @param <T> type of the gateway to retrieve
  @return StaticFileServerHandler if flink-runtime-web is in the classpath; Otherwise Optional.empty
  @throws IOException if we cannot create the StaticFileServerHandler