/**
   * Returns an empty {@code ImmutableClassToInstanceMap}.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   *
   * @since 19.0
   */
  @SuppressWarnings("unchecked")
  public static <B> ImmutableClassToInstanceMap<B> of() {
    return (ImmutableClassToInstanceMap<B>) EMPTY;
  }

  /**
   * Returns an {@code ImmutableClassToInstanceMap} containing a single entry.
   *

      for (Object element : elements) {
        @SuppressWarnings("unchecked")
        Entry<String, Integer> entry = (Entry<String, Integer>) element;
        multimap.put(entry.getKey(), entry.getValue());
      }
      return multimap.entries();
    }

    abstract Multimap<String, Integer> createMultimap();

    @Override
    @SuppressWarnings("unchecked")
    public Entry<String, Integer>[] createArray(int length) {

@GwtCompatible
@ElementTypesAreNonnullByDefault
final class Absent<T> extends Optional<T> {
  static final Absent<Object> INSTANCE = new Absent<>();

  @SuppressWarnings("unchecked") // implementation is "fully variant"
  static <T> Optional<T> withType() {
    return (Optional<T>) INSTANCE;
  }

  private Absent() {}

  @Override
  public boolean isPresent() {
    return false;
  }

@GwtCompatible
@ElementTypesAreNonnullByDefault
final class Absent<T> extends Optional<T> {
  static final Absent<Object> INSTANCE = new Absent<>();

  @SuppressWarnings("unchecked") // implementation is "fully variant"
  static <T> Optional<T> withType() {
    return (Optional<T>) INSTANCE;
  }

  private Absent() {}

  @Override
  public boolean isPresent() {
    return false;
  }

    @CheckForNull
    public Collection<V> get(@CheckForNull Object key) {
      Collection<V> result = unfiltered.asMap().get(key);
      if (result == null) {
        return null;
      }
      @SuppressWarnings("unchecked") // key is equal to a K, if not a K itself
      K k = (K) key;
      result = filterCollection(result, new ValuePredicate(k));
      return result.isEmpty() ? null : result;
    }

    @Override

                  // Other tests will verify what real, warning-free usage looks like
                  // but here we have to do some serious fudging
                  @Override
                  @SuppressWarnings({"unchecked", "rawtypes"})
                  public Map<TypeToken, Object> create(Object... elements) {
                    ImmutableTypeToInstanceMap.Builder<Object> builder =
                        ImmutableTypeToInstanceMap.builder();

 * @author George van den Driessche
 */
@GwtIncompatible
public abstract class FeatureSpecificTestSuiteBuilder<
    B extends FeatureSpecificTestSuiteBuilder<B, G>, G> {
  @SuppressWarnings("unchecked")
  protected B self() {
    return (B) this;
  }

  // Test Data

  private @Nullable G subjectGenerator;
  // Gets run before every test.
  private Runnable setUp;

                    }
                    List<Supplier<Object>> list =
                            res3.stream().map(this::compile).collect(Collectors.toList());
                    //noinspection unchecked
                    return () -> (Q) list(list);
                }
                if (key.getRawType() == Map.class) {
                    Key<?> k = key.getTypeParameter(0);

 *
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
public final class ImmutableSortedMap<K, V> extends ForwardingImmutableMap<K, V>
    implements SortedMap<K, V> {

  @SuppressWarnings("unchecked")
  static final Comparator<?> NATURAL_ORDER = Ordering.natural();

  // This reference is only used by GWT compiler to infer the keys and values
  // of the map that needs to be serialized.

   * @return {@code Optional.of(onlyElement)} if the stream has exactly one element (must not be
   *     {@code null}) and returns {@code Optional.empty()} if it has none.
   */
  @SuppressWarnings("unchecked")
  public static <T> Collector<T, ?, Optional<T>> toOptional() {
    return (Collector) TO_OPTIONAL;
  }

  private static final Object NULL_PLACEHOLDER = new Object();