}

  private class FakeService extends AbstractExecutionThreadService implements TearDown {

    private final ExecutorService executor = Executors.newSingleThreadExecutor();

    FakeService() {
      tearDownStack.addTearDown(this);
    }

    volatile int startupCalled = 0;
    volatile int shutdownCalled = 0;
    volatile int runCalled = 0;

    class MyError extends Error {}
    final CyclicBarrier barrier = new CyclicBarrier(2);
    // we need to make sure the error gets thrown on a different thread.
    ExecutorService service = Executors.newSingleThreadExecutor();
    try {
      final SequentialExecutor executor = new SequentialExecutor(service);
      Runnable errorTask =
          new Runnable() {
            @Override
            public void run() {

  }

  private class FakeService extends AbstractExecutionThreadService implements TearDown {

    private final ExecutorService executor = Executors.newSingleThreadExecutor();

    FakeService() {
      tearDownStack.addTearDown(this);
    }

    volatile int startupCalled = 0;
    volatile int shutdownCalled = 0;
    volatile int runCalled = 0;

    class MyError extends Error {}
    final CyclicBarrier barrier = new CyclicBarrier(2);
    // we need to make sure the error gets thrown on a different thread.
    ExecutorService service = Executors.newSingleThreadExecutor();
    try {
      final SequentialExecutor executor = new SequentialExecutor(service);
      Runnable errorTask =
          new Runnable() {
            @Override
            public void run() {

  private static final long HALF_SECOND_NANOS = NANOSECONDS.convert(1L, SECONDS) / 2;

  public void testShutdownAndAwaitTermination_immediateShutdown() throws Exception {
    ExecutorService service = Executors.newSingleThreadExecutor();
    assertTrue(shutdownAndAwaitTermination(service, 1L, SECONDS));
    assertTrue(service.isTerminated());
  }

        Path dirToDelete = fs.getPath("dir/b/i");
        Path changingFile = dirToDelete.resolve("j/l");
        Path symlinkTarget = fs.getPath("/dontdelete");

        ExecutorService executor = Executors.newSingleThreadExecutor();
        startDirectorySymlinkSwitching(changingFile, symlinkTarget, executor);

        try {
          for (int i = 0; i < iterations; i++) {
            try {

        Path dirToDelete = fs.getPath("dir/b/i");
        Path changingFile = dirToDelete.resolve("j/l");
        Path symlinkTarget = fs.getPath("/dontdelete");

        ExecutorService executor = Executors.newSingleThreadExecutor();
        startDirectorySymlinkSwitching(changingFile, symlinkTarget, executor);

        try {
          for (int i = 0; i < iterations; i++) {
            try {

  private static final long HALF_SECOND_NANOS = NANOSECONDS.convert(1L, SECONDS) / 2;

  public void testShutdownAndAwaitTermination_immediateShutdown() throws Exception {
    ExecutorService service = Executors.newSingleThreadExecutor();
    assertTrue(shutdownAndAwaitTermination(service, 1L, SECONDS));
    assertTrue(service.isTerminated());
  }

   * despite not throwing a RejectedExecutionException synchronously with the call to {@code
   * execute}. If this behaviour is problematic, use an Executor with a single thread (e.g. {@link
   * Executors#newSingleThreadExecutor}).
   *
   * @since 23.3 (since 23.1 as {@code sequentialExecutor})
   */
  @GwtIncompatible
  public static Executor newSequentialExecutor(Executor delegate) {
    return new SequentialExecutor(delegate);

import static com.google.common.util.concurrent.MoreExecutors.listeningDecorator;
import static java.lang.Math.max;
import static java.lang.Thread.State.WAITING;
import static java.util.concurrent.Executors.newSingleThreadExecutor;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.MINUTES;
import static java.util.concurrent.TimeUnit.NANOSECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;