* @since 2.0
 */
@GwtCompatible
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);
  }

  /**

            "chile", "peso",
            "switzerland", "franc");
    HashBiMap<String, String> bimap = HashBiMap.create(map);
    assertEquals("dollar", bimap.get("canada"));
    assertEquals("canada", bimap.inverse().get("dollar"));
  }

  private static final int N = 1000;

  public void testBashIt() throws Exception {
    BiMap<Integer, Integer> bimap = HashBiMap.create(N);
    BiMap<Integer, Integer> inverse = bimap.inverse();

import com.google.common.base.Ticker;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.BiMap;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.HashBiMap;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.HashMultiset;
import com.google.common.collect.ImmutableBiMap;
import com.google.common.collect.ImmutableCollection;

    assertThat(converter.convert(null)).isNull();
    assertThat(converter.reverse().convert(null)).isNull();
  }

  public void testAsConverter_isAView() throws Exception {
    BiMap<String, Integer> biMap = HashBiMap.create();
    biMap.put("one", 1);
    biMap.put("two", 2);
    Converter<String, Integer> converter = Maps.asConverter(biMap);

    assertEquals((Integer) 1, converter.convert("one"));

 * bimap containing the same entries as this bimap but with reversed keys and values.
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableBiMap}
 *   <li>{@link HashBiMap}
 *   <li>{@link EnumBiMap}
 *   <li>{@link EnumHashBiMap}
 * </ul>
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap}</a>.

  }

  public void testCreate() {
    EnumHashBiMap<Currency, String> bimap = EnumHashBiMap.create(Currency.class);
    assertTrue(bimap.isEmpty());
    assertEquals("{}", bimap.toString());
    assertEquals(HashBiMap.create(), bimap);
    bimap.put(Currency.DOLLAR, "dollar");
    assertEquals("dollar", bimap.get(Currency.DOLLAR));
    assertEquals(Currency.DOLLAR, bimap.inverse().get("dollar"));
  }

      }
    };
  }

  enum BiMapImpl implements MapsImplEnum {
    HashBiMapImpl {
      @Override
      public <K extends Comparable<K>, V> BiMap<K, V> create(Map<K, V> map) {
        return HashBiMap.create(map);
      }
    },
    ImmutableBiMapImpl {
      @Override
      public <K extends Comparable<K>, V> BiMap<K, V> create(Map<K, V> map) {
        return ImmutableBiMap.copyOf(map);
      }
    };

  public void testCreate() {
    EnumBiMap<Currency, Country> bimap = EnumBiMap.create(Currency.class, Country.class);
    assertTrue(bimap.isEmpty());
    assertEquals("{}", bimap.toString());
    assertEquals(HashBiMap.create(), bimap);
    bimap.put(Currency.DOLLAR, Country.CANADA);
    assertEquals(Country.CANADA, bimap.get(Currency.DOLLAR));
    assertEquals(Currency.DOLLAR, bimap.inverse().get(Country.CANADA));
  }

    assertThat(converter.convert(null)).isNull();
    assertThat(converter.reverse().convert(null)).isNull();
  }

  public void testAsConverter_isAView() throws Exception {
    BiMap<String, Integer> biMap = HashBiMap.create();
    biMap.put("one", 1);
    biMap.put("two", 2);
    Converter<String, Integer> converter = Maps.asConverter(biMap);

    assertEquals((Integer) 1, converter.convert("one"));

   *
   * <p>It is imperative that the user manually synchronize on the returned map when accessing any
   * of its collection views:
   *
   * {@snippet :
   * BiMap<Long, String> map = Maps.synchronizedBiMap(HashBiMap.create());
   * ...
   * Set<Long> set = map.keySet();  // Needn't be in synchronized block
   * ...
   * synchronized (map) {  // Synchronizing on map, not set!