* java.util.LinkedHashMap LinkedHashMap} and {@link ImmutableMap#copyOf(Map)} rather than
     * {@code ImmutableMap.Builder}.
     *
     * @since 31.1
     */
    public ImmutableMap<K, V> buildKeepingLast() {
      return build(false);
    }

    @VisibleForTesting // only for testing JDK backed implementation
    ImmutableMap<K, V> buildJdkBacked() {
      checkState(

   * @throws NullPointerException if any key or value in {@code map} is null
   */
  public static <K, V> ImmutableMap<K, V> copyOf(Map<? extends K, ? extends V> map) {
    if ((map instanceof ImmutableMap) && !(map instanceof SortedMap)) {
      @SuppressWarnings("unchecked") // safe since map is not writable
      ImmutableMap<K, V> kvMap = (ImmutableMap<K, V>) map;
      if (!kvMap.isPartialView()) {
        return kvMap;
      }
    }

        ImmutableMap::copyOf);
  }

  @SuppressWarnings("unchecked") // An empty map works for all types.
  public static <K, V> ImmutableMap<K, V> of() {
    return (ImmutableMap<K, V>) RegularImmutableMap.EMPTY;
  }

  public static <K, V> ImmutableMap<K, V> of(K k1, V v1) {
    return ImmutableBiMap.of(k1, v1);
  }

  public static <K, V> ImmutableMap<K, V> of(K k1, V v1, K k2, V v2) {

      this(map, asImmutableList(entries));
    }

    RegularEntrySet(ImmutableMap<K, V> map, ImmutableList<Entry<K, V>> entries) {
      this.map = map;
      this.entries = entries;
    }

    @Override
    ImmutableMap<K, V> map() {
      return map;
    }

    @Override
    @GwtIncompatible // not used in GWT

import org.jspecify.annotations.Nullable;

/**
 * {@code keySet()} implementation for {@link ImmutableMap}.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible
final class ImmutableMapKeySet<K, V> extends IndexedImmutableSet<K> {
  private final ImmutableMap<K, V> map;

  ImmutableMapKeySet(ImmutableMap<K, V> map) {
    this.map = map;
  }

  @Override
  public int size() {

                return ae;
              }
            });
    ImmutableMap<AnEnum, AnEnum> copy = immutableEnumMap(map);
    assertThat(copy.entrySet()).containsExactly(mapEntry(AnEnum.A, AnEnum.A));
  }

  public void testEmptyImmutableEnumMap() {
    ImmutableMap<AnEnum, String> map = immutableEnumMap(ImmutableMap.<AnEnum, String>of());
    assertEquals(ImmutableMap.of(), map);
  }

  public void testImmutableEnumMapOrdering() {

  static final class RegularEntrySet<K, V> extends ImmutableMapEntrySet<K, V> {
    private final transient ImmutableMap<K, V> map;
    private final transient ImmutableList<Entry<K, V>> entries;

    RegularEntrySet(ImmutableMap<K, V> map, Entry<K, V>[] entries) {
      this(map, asImmutableList(entries));
    }

    RegularEntrySet(ImmutableMap<K, V> map, ImmutableList<Entry<K, V>> entries) {
      this.map = map;
      this.entries = entries;

                return ae;
              }
            });
    ImmutableMap<AnEnum, AnEnum> copy = immutableEnumMap(map);
    assertThat(copy.entrySet()).containsExactly(mapEntry(AnEnum.A, AnEnum.A));
  }

  public void testEmptyImmutableEnumMap() {
    ImmutableMap<AnEnum, String> map = immutableEnumMap(ImmutableMap.<AnEnum, String>of());
    assertEquals(ImmutableMap.of(), map);
  }

  public void testImmutableEnumMapOrdering() {

import org.jspecify.annotations.Nullable;

/**
 * {@code values()} implementation for {@link ImmutableMap}.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible
final class ImmutableMapValues<K, V> extends ImmutableCollection<V> {
  private final ImmutableMap<K, V> map;

  ImmutableMapValues(ImmutableMap<K, V> map) {
    this.map = map;
  }

  @Override
  public int size() {

 * @author Gregory Kick
 */
@GwtCompatible
final class RegularImmutableMap<K, V> extends ImmutableMap<K, V> {
  @SuppressWarnings("unchecked")
  static final ImmutableMap<Object, Object> EMPTY =
      new RegularImmutableMap<>((Entry<Object, Object>[]) ImmutableMap.EMPTY_ENTRY_ARRAY, null, 0);

  /**
   * Closed addressing tends to perform well even with high load factors. Being conservative here