// 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
  }

@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);
  }

  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);

        reader.setScrollSize(1000);
        int count = 0;
        Set<String> valueSet = Collections.synchronizedSet(new HashSet<>());
        Map<String, Object> source;
        while ((source = reader.read()) != null) {
            assertTrue(source.get("field1").toString().startsWith("test"));
            valueSet.add(source.get("field1").toString());
            count++;
        }

@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}.
   *

 * MoreExecutors#listeningDecorator}.
 *
 * @author Sven Mawson
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public class ListenableFutureTask<V extends @Nullable Object> extends FutureTask<V>
    implements ListenableFuture<V> {
  // TODO(cpovirk): explore ways of making ListenableFutureTask final. There are some valid reasons

 */
@GwtIncompatible
@ElementTypesAreNonnullByDefault
abstract class AbstractNavigableMap<K extends @Nullable Object, V extends @Nullable Object>
    extends IteratorBasedAbstractMap<K, V> implements NavigableMap<K, V> {

  @Override
  @CheckForNull
  public abstract V get(@CheckForNull Object key);

  @Override
  @CheckForNull
  public Entry<K, V> firstEntry() {

    }

    @Override
    public void acceptAllColumnMap(Entity entity, Map<String, ? extends Object> allColumnMap) {
    }

    @Override
    public Map<String, Object> extractPrimaryKeyMap(Entity entity) {
        return null;
    }

    @Override
    public Map<String, Object> extractAllColumnMap(Entity entity) {
        return null;