// stored in the builder, which may use it to throw an exception later.
  static <K, V> RegularImmutableMap<K, V> create(
      int n, @Nullable Object[] alternatingKeysAndValues, @Nullable Builder<K, V> builder) {
    if (n == 0) {
      @SuppressWarnings("unchecked")
      RegularImmutableMap<K, V> empty = (RegularImmutableMap<K, V>) EMPTY;
      return empty;

  ImmutableCollection() {}

  public abstract UnmodifiableIterator<E> iterator();

  public boolean contains(@Nullable Object object) {
    return object != null && super.contains(object);
  }

  public final boolean add(E e) {
    throw new UnsupportedOperationException();
  }

  public final boolean remove(@Nullable Object object) {
    throw new UnsupportedOperationException();
  }

import java.util.List;
import java.util.Map.Entry;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A container class for the five sample elements we need for testing.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public class SampleElements<E extends @Nullable Object> implements Iterable<E> {
  // TODO: rename e3, e4 => missing1, missing2
  private final E e0;

import java.util.List;
import java.util.Map.Entry;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A container class for the five sample elements we need for testing.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public class SampleElements<E extends @Nullable Object> implements Iterable<E> {
  // TODO: rename e3, e4 => missing1, missing2
  private final E e0;

      return standardSubMultiset(lowerBound, lowerBoundType, upperBound, upperBoundType);
    }

    @Override
    public int count(@Nullable Object element) {
      return standardCount(element);
    }

    @Override
    public boolean equals(@Nullable Object object) {
      return standardEquals(object);
    }

    @Override
    public int hashCode() {
      return standardHashCode();
    }

    try {
      // any ClassCastExceptions and NullPointerExceptions are caught
      @SuppressWarnings({"unchecked", "nullness"})
      SortedSet<@Nullable Object> self = (SortedSet<@Nullable Object>) this;
      Object ceiling = self.tailSet(object).first();
      return unsafeCompare(comparator(), ceiling, object) == 0;

 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class HashBiMap<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMap<K, V> implements BiMap<K, V>, Serializable {

  /** Returns a new, empty {@code HashBiMap} with the default initial capacity (16). */
  public static <K extends @Nullable Object, V extends @Nullable Object> HashBiMap<K, V> create() {
    return create(16);
  }

  /**

              }

              @Override
              public boolean equals(@Nullable Object o) {
                return map.equals(o);
              }

              @Override
              public String toString() {
                return map.toString();
              }

              @Override
              public @Nullable String remove(Object key) {
                return map.remove(key);
              }

@ElementTypesAreNonnullByDefault
class CompactLinkedHashMap<K extends @Nullable Object, V extends @Nullable Object>
    extends CompactHashMap<K, V> {
  // TODO(lowasser): implement removeEldestEntry so this can be used as a drop-in replacement

  /** Creates an empty {@code CompactLinkedHashMap} instance. */
  public static <K extends @Nullable Object, V extends @Nullable Object>
      CompactLinkedHashMap<K, V> create() {

import com.google.common.annotations.GwtCompatible;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A supertype for filtered {@link SetMultimap} implementations.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
interface FilteredSetMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends FilteredMultimap<K, V>, SetMultimap<K, V> {
  @Override