* differs.)
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 * @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);

  /**

  // 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;
    } else if (n == 1) {

  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) {
    return new RegularImmutableMap<K, V>(entryOf(k1, v1), entryOf(k2, v2));
  }

  }

  @SuppressWarnings("unchecked")
  @Override
  public @Nullable V get(@Nullable Object key) {
    Object result =
        RegularImmutableMap.get(keyHashTable, alternatingKeysAndValues, size, keyOffset, key);
    /*
     * We can't simply cast the result of `RegularImmutableMap.get` to V because of a bug in our
     * nullness checker (resulting from https://github.com/jspecify/checker-framework/issues/8).
     */

   * code.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings("unchecked")
  public static <K, V> ImmutableMap<K, V> of() {
    return (ImmutableMap<K, V>) RegularImmutableMap.EMPTY;
  }

  /**
   * Returns an immutable map containing a single entry. This map behaves and performs comparably to
   * {@link Collections#singletonMap} but will not accept a null key or value. It is preferable

import static com.google.common.collect.ImmutableMapEntry.createEntryArray;
import static com.google.common.collect.Maps.immutableEntry;
import static com.google.common.collect.RegularImmutableMap.MAX_HASH_BUCKET_LENGTH;
import static com.google.common.collect.RegularImmutableMap.checkNoConflictInKeyBucket;
import static java.util.Objects.requireNonNull;

import com.google.common.annotations.GwtCompatible;

    return RegularImmutableMap.fromEntries(entryOf(k1, v1), entryOf(k2, v2));
  }

  /**
   * Returns an immutable map containing the given entries, in order.
   *
   * @throws IllegalArgumentException if duplicate keys are provided
   */
  public static <K, V> ImmutableMap<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3) {

  private final ImmutableBiMap<V, K> inverse;

  @SuppressWarnings("unchecked") // used only for the empty map, which works for any types
  RegularImmutableBiMap() {
    super(new RegularImmutableMap<K, V>(new HashMap<K, V>()));
    this.inverse = (ImmutableBiMap<V, K>) this;
  }

  RegularImmutableBiMap(ImmutableMap<K, V> delegate) {
    super(delegate);

    for (int i = 0; i < 10; i++) {
      builder.put(i, i);
    }
    Object[] builderArrayAfterPuts = builder.alternatingKeysAndValues;
    RegularImmutableMap<Integer, Integer> map =
        (RegularImmutableMap<Integer, Integer>) builder.buildOrThrow();
    Object[] mapInternalArray = map.alternatingKeysAndValues;
    assertSame(builderArray, builderArrayAfterPuts);

import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@code Entry} for {@link ImmutableMap} that adds extra methods to traverse hash
 * buckets for the key and the value. This allows reuse in {@link RegularImmutableMap} and {@link
 * RegularImmutableBiMap}, which don't have to recopy the entries created by their {@code Builder}
 * implementations.
 *