* to be made.
 *
 * <p>The declaration methods must be public.
 */
@AndroidIncompatible // only used by android incompatible tests.
abstract class SubtypeTester implements Cloneable {

  /** Annotates a public method that declares subtype assertion. */
  @RequiredModifiers(Modifier.PUBLIC)
  @Retention(RetentionPolicy.RUNTIME)
  @Target(ElementType.METHOD)
  @interface TestSubtype {

    ClosingFuture<Closeable> closingFuture =
        ClosingFuture.submit(
            new ClosingCallable<Closeable>() {
              @Override
              public Closeable call(DeferredCloser closer) throws Exception {
                return closer.eventuallyClose(mockCloseable, executor);
              }
            },
            executor);
    FluentFuture<Closeable> unused = closingFuture.finishToFuture();

    public <C extends @Nullable Object & @Nullable Closeable> C eventuallyClose(
        @ParametricNullness C closeable, Executor closingExecutor) {
      checkNotNull(closingExecutor);
      if (closeable != null) {
        list.add(closeable, closingExecutor);
      }
      return closeable;
    }
  }

  /**
   * An operation that computes a result.
   *

    boolean finalized = finalizeCount.tryAcquire(5, TimeUnit.SECONDS);
    assertTrue(finalized);

    Field sepFrqUserFrqF = sepFrqUserC.getField("frq");
    Closeable frq = (Closeable) sepFrqUserFrqF.get(null);
    frq.close();

    return new WeakReference<ClassLoader>(sepLoader);
  }

  private URL[] getClassPathUrls() {
    ClassLoader classLoader = getClass().getClassLoader();

   * @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);
    }

    return closeable;
  }

  /**

   *     method
   * @throws IOException if {@code swallowIOException} is false and {@link Flushable#flush} throws
   *     an {@code IOException}.
   * @see Closeables#close
   */
  public static void flush(Flushable flushable, boolean swallowIOException) throws IOException {
    try {
      flushable.flush();
    } catch (IOException e) {
      if (swallowIOException) {

  public void testCopyExceptions() {
    if (Closer.create().suppressor instanceof LoggingSuppressor) {
      // test that exceptions are logged

      TestLogHandler logHandler = new TestLogHandler();
      Closeables.logger.addHandler(logHandler);
      try {
        for (CharSource in : BROKEN_SOURCES) {
          runFailureTest(in, newNormalCharSink());
          assertTrue(logHandler.getStoredLogRecords().isEmpty());

              @Override
              public Closeable call(DeferredCloser closer) throws Exception {
                return closer.eventuallyClose(mockCloseable, executor);
              }
            },
            executor);
    FluentFuture<Closeable> unused = closingFuture.finishToFuture();
    assertThrows(
        IllegalStateException.class,
        () -> {

  public void testCopyExceptions() {
    if (Closer.create().suppressor instanceof LoggingSuppressor) {
      // test that exceptions are logged

      TestLogHandler logHandler = new TestLogHandler();
      Closeables.logger.addHandler(logHandler);
      try {
        for (ByteSource in : BROKEN_SOURCES) {
          runFailureTest(in, newNormalByteSink());
          assertTrue(logHandler.getStoredLogRecords().isEmpty());

/**
 * Provides utility methods for working with character streams.
 *
 * <p>Some of the methods in this class take arguments with a generic type of {@code Readable &
 * Closeable}. A {@link java.io.Reader} implements both of those interfaces. Similarly for {@code
 * Appendable & Closeable} and {@link java.io.Writer}.
 *
 * @author Chris Nokleberg
 * @author Bin Zhu
 * @author Colin Decker
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible