* </p>
     *
     * @param closeable the closeable object
     * @see Closeable#close()
     */
    public static void close(final Closeable closeable) {
        if (closeable == null) {
            return;
        }
        try {

  @SuppressWarnings("IdentifierName")
  public static void close(@Nullable Closeable closeable, boolean swallowIOException)
      throws IOException {
    if (closeable == null) {
      return;
    }
    try {
      closeable.close();
    } catch (IOException e) {
      if (swallowIOException) {
        logger.log(Level.WARNING, "IOException thrown while closing Closeable.", e);
      } else {
        throw e;
      }
    }
  }

  /**
   * Registers the given {@code closeable} to be closed when this {@code Closer} is {@linkplain
   * #close closed}.
   *
   * @return the given {@code closeable}
   */
  // close. this word no longer has any meaning to me.
  @CanIgnoreReturnValue
  @ParametricNullness
  public <C extends @Nullable Closeable> C register(@ParametricNullness C closeable) {
    if (closeable != null) {
      stack.addFirst(closeable);

      this.closeable = closeable;
      this.thrown = thrown;
      this.suppressed = suppressed;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      if (obj instanceof Suppression) {
        Suppression other = (Suppression) obj;
        return closeable.equals(other.closeable)
            && thrown.equals(other.thrown)

@J2ktIncompatible
public class ClosingFutureLeakTest extends TestCase {
  public void testLeak() {
    TestCloseable closeable = new TestCloseable("closeable");
    awaitClear(leakClosingFuture(closeable));
    assertThat(closeable.awaitClosed()).isTrue();
  }

  private WeakReference<ClosingFuture<String>> leakClosingFuture(TestCloseable closeable) {
    ClosingFuture<String> willCloseCloseable =
        ClosingFuture.submit(
            closer -> {

@J2ktIncompatible
public class ClosingFutureLeakTest extends TestCase {
  public void testLeak() {
    TestCloseable closeable = new TestCloseable("closeable");
    awaitClear(leakClosingFuture(closeable));
    assertThat(closeable.awaitClosed()).isTrue();
  }

  private WeakReference<ClosingFuture<String>> leakClosingFuture(TestCloseable closeable) {
    ClosingFuture<String> willCloseCloseable =
        ClosingFuture.submit(
            closer -> {

  final ExecutorService closingExecutor = newSingleThreadExecutor();

  final TestCloseable closeable1 = new TestCloseable("closeable1");
  final TestCloseable closeable2 = new TestCloseable("closeable2");
  final TestCloseable closeable3 = new TestCloseable("closeable3");
  final TestCloseable closeable4 = new TestCloseable("closeable4");

  final Waiter waiter = new Waiter();

  final ExecutorService closingExecutor = newSingleThreadExecutor();

  final TestCloseable closeable1 = new TestCloseable("closeable1");
  final TestCloseable closeable2 = new TestCloseable("closeable2");
  final TestCloseable closeable3 = new TestCloseable("closeable3");
  final TestCloseable closeable4 = new TestCloseable("closeable4");

  final Waiter waiter = new Waiter();

      this.closeable = closeable;
      this.thrown = thrown;
      this.suppressed = suppressed;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      if (obj instanceof Suppression) {
        Suppression other = (Suppression) obj;
        return closeable.equals(other.closeable)
            && thrown.equals(other.thrown)

    ClosingFuture<Closeable> closingFuture =
        ClosingFuture.submit(closer -> closer.eventuallyClose(mockCloseable, executor), executor);
    FluentFuture<Closeable> unused = closingFuture.finishToFuture();
    assertThrows(
        IllegalStateException.class,
        () -> {
          FluentFuture<Closeable> unused2 = closingFuture.finishToFuture();
        });
  }