return SHORT_DELAY_MS / 4;
  }

  /** Returns a new Date instance representing a time delayMillis milliseconds in the future. */
  Date delayedDate(long delayMillis) {
    return new Date(System.currentTimeMillis() + delayMillis);
  }

  /** The first exception encountered if any threadAssertXXX method fails. */
  private final AtomicReference<Throwable> threadFailure = new AtomicReference<>(null);

  /**

  @SuppressWarnings("GoodTime") // reading system time without TimeSource
  public static void touch(File file) throws IOException {
    checkNotNull(file);
    if (!file.createNewFile() && !file.setLastModified(System.currentTimeMillis())) {
      throw new IOException("Unable to update modification time of " + file);
    }
  }

  /**
   * Creates any necessary but nonexistent parent directories of the specified file. Note that if

  @SuppressWarnings("GoodTime") // reading system time without TimeSource
  public static void touch(File file) throws IOException {
    checkNotNull(file);
    if (!file.createNewFile() && !file.setLastModified(System.currentTimeMillis())) {
      throw new IOException("Unable to update modification time of " + file);
    }
  }

  /**
   * Creates any necessary but nonexistent parent directories of the specified file. Note that if

  public static void touch(Path path) throws IOException {
    checkNotNull(path);

    try {
      Files.setLastModifiedTime(path, FileTime.fromMillis(System.currentTimeMillis()));
    } catch (NoSuchFileException e) {
      try {
        Files.createFile(path);
      } catch (FileAlreadyExistsException ignore) {

  public static void touch(Path path) throws IOException {
    checkNotNull(path);

    try {
      Files.setLastModifiedTime(path, FileTime.fromMillis(System.currentTimeMillis()));
    } catch (NoSuchFileException e) {
      try {
        Files.createFile(path);
      } catch (FileAlreadyExistsException ignore) {