assertEquals(1, Iterators.size(registry.getSubscribers(new Object())));
    assertEquals(1, Iterators.size(registry.getSubscribers(1)));

    registry.register(new IntegerSubscriber());
    assertEquals(3, Iterators.size(registry.getSubscribers("")));
    assertEquals(1, Iterators.size(registry.getSubscribers(new Object())));
    assertEquals(2, Iterators.size(registry.getSubscribers(1)));
  }

	xioutil "github.com/minio/minio/internal/ioutil"
	"github.com/minio/pkg/v3/console"
)

// metaCacheEntry is an object or a directory within an unknown bucket.
type metaCacheEntry struct {
	// name is the full name of the object including prefixes
	name string
	// Metadata. If none is present it is not an object but only a prefix.
	// Entries without metadata will only be present in non-recursive scans.
	metadata []byte

@ElementTypesAreNonnullByDefault
public abstract class AbstractBiMapTester<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMapTester<K, V> {

  @Override
  protected BiMap<K, V> getMap() {
    return (BiMap<K, V>) super.getMap();
  }

  static <K extends @Nullable Object, V extends @Nullable Object> Entry<V, K> reverseEntry(
      Entry<K, V> entry) {
    return mapEntry(entry.getValue(), entry.getKey());

  @CheckForNull
  public V get(@CheckForNull Object key) {
    return singleKey.equals(key) ? singleValue : null;
  }

  @Override
  public int size() {
    return 1;
  }

  @Override
  public void forEach(BiConsumer<? super K, ? super V> action) {
    checkNotNull(action).accept(singleKey, singleValue);
  }

  @Override
  public boolean containsKey(@CheckForNull Object key) {
    return singleKey.equals(key);
  }

    // it still should only have executed twice due to memoization
    assertEquals(2, countingSupplier.calls);
  }

  public void testOfInstanceSuppliesSameInstance() {
    Object toBeSupplied = new Object();
    Supplier<Object> objectSupplier = Suppliers.ofInstance(toBeSupplied);
    assertSame(toBeSupplied, objectSupplier.get());
    assertSame(toBeSupplied, objectSupplier.get()); // idempotent
  }

    // it still should only have executed twice due to memoization
    assertEquals(2, countingSupplier.calls);
  }

  public void testOfInstanceSuppliesSameInstance() {
    Object toBeSupplied = new Object();
    Supplier<Object> objectSupplier = Suppliers.ofInstance(toBeSupplied);
    assertSame(toBeSupplied, objectSupplier.get());
    assertSame(toBeSupplied, objectSupplier.get()); // idempotent
  }

  static <V extends @Nullable Object, X extends Exception> V getChecked(
      Future<V> future, Class<X> exceptionClass) throws X {
    return getChecked(bestGetCheckedTypeValidator(), future, exceptionClass);
  }

  /** Implementation of {@link Futures#getChecked(Future, Class)}. */
  @CanIgnoreReturnValue
  @VisibleForTesting
  @ParametricNullness
  static <V extends @Nullable Object, X extends Exception> V getChecked(

        assertThat(map, is(notNullValue()));
        assertThat(map.isEmpty(), is(false));
        assertThat(map.get(Foo.class.getTypeParameters()[0]), is(sameClass(Object.class)));
    }

    /**
     * @throws Exception
     */
    public void testGenericMethod() throws Exception {
        final Map<TypeVariable<?>, Type> map = GenericsUtil.getTypeVariableMap(Fuga.class);

  }

  /**
   * Incorporate additional requirements into an existing requirements object.
   *
   * @param requirements the existing requirements object
   * @param moreRequirements more requirements to incorporate
   * @param source the source of the additional requirements (used only for error reporting)
   * @return the existing requirements object, modified to include the additional requirements

@ElementTypesAreNonnullByDefault
public final class Callables {
  private Callables() {}

  /** Creates a {@code Callable} which immediately returns a preset value each time it is called. */
  public static <T extends @Nullable Object> Callable<T> returning(@ParametricNullness T value) {
    return () -> value;
  }

  /**
   * Creates an {@link AsyncCallable} from a {@link Callable}.
   *