* this method to use a custom {@link Executor}, which may configure its worker thread with a
   * specific name, thread group or priority. The returned executor's {@link
   * Executor#execute(Runnable) execute()} method is called when this service is started and
   * stopped, and should return promptly.
   */
  protected Executor executor() {
    return command -> newThread(threadNameSupplier.get(), command).start();

  @SuppressWarnings("ThreadPriorityCheck") // TODO: b/175898629 - Consider onSpinWait.
  static void awaitWaiting(Thread t) {
    while (true) {
      Thread.State state = t.getState();
      switch (state) {
        case RUNNABLE:
        case BLOCKED:
          Thread.yield();
          break;
        case WAITING:
          return;
        default:
          throw new AssertionError("unexpected state: " + state);
      }

     * @param waitController The runnable to control waiting between requests.
     * @return A Promise that will be resolved with the SuggestIndexResponse or rejected with an error.
     */
    public Deferred<SuggestIndexResponse>.Promise indexFromDocument(final Supplier<DocumentReader> reader, final int docPerReq,
            final Runnable waitController) {
        ensureOperations();

 *     ...
 *     this.serverSocket = new ServerSocket(...);
 *     this.cleanable = cleaner.register(this, closeServerSocketRunnable(serverSocket));
 *     ...
 *   }
 *
 *   private static Runnable closeServerSocketRunnable(ServerSocket serverSocket) {
 *     return () -> {
 *       if (!serverSocket.isClosed()) {
 *         ...log a message about how nobody called close()...
 *         try {

 *     ...
 *     this.serverSocket = new ServerSocket(...);
 *     this.cleanable = cleaner.register(this, closeServerSocketRunnable(serverSocket));
 *     ...
 *   }
 *
 *   private static Runnable closeServerSocketRunnable(ServerSocket serverSocket) {
 *     return () -> {
 *       if (!serverSocket.isClosed()) {
 *         ...log a message about how nobody called close()...
 *         try {

 * collected, and this class can detect when the main class loader has been garbage collected and
 * stop itself.
 */
public class Finalizer implements Runnable {

  private static final Logger logger = Logger.getLogger(Finalizer.class.getName());

  /**
   * Starts the Finalizer thread. FinalizableReferenceQueue calls this method reflectively.
   *

 * It is responsible for fetching URLs from the queue, accessing the content,
 * processing the response, and extracting child URLs.
 *
 * <p>
 * This class implements the {@link Runnable} interface, allowing it to be executed in a separate thread.
 * It uses various services and components, such as {@link UrlQueueService}, {@link DataService},

      this.adapterExecutor = checkNotNull(adapterExecutor);
    }

    @Override
    protected Future<V> delegate() {
      return delegate;
    }

    @Override
    public void addListener(Runnable listener, Executor exec) {
      executionList.add(listener, exec);

      // When a listener is first added, we run a task that will wait for the delegate to finish,
      // and when it is done will run the listeners.

    Service service =
        new TestService() {
          @Override
          protected Executor executor() {
            return new Executor() {
              @Override
              public void execute(Runnable command) {}
            };
          }

          @Override
          protected String serviceName() {
            return "Foo";
          }
        };
    TimeoutException e =

  }

  @SuppressWarnings("Java8ApiChecker")
  static class MyServerExampleWithCleaner implements AutoCloseable {
    private static final Cleaner cleaner = Cleaner.create();

    private static Runnable closeServerSocketRunnable(
        ServerSocket serverSocket, AtomicBoolean cleanerRan) {
      return () -> {
        try {
          serverSocket.close();
          cleanerRan.set(true);