* @return 指定されたキーと値を持つ{@link HashMap}を構築するための{@literal Maps}
     */
    public static <KEY, VALUE> Maps<KEY, VALUE> hashMap(final KEY key, final VALUE value) {
        return new Maps<>(new HashMap<KEY, VALUE>()).$(key, value);
    }

    /**
     * 指定されたキーと値を持つ{@link Hashtable}を構築するための{@literal Maps}を返します。
     *
     * @param <KEY>
     *            <code>Map</code>のキーの型
     * @param <VALUE>

 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#maps">{@code Maps}</a>.
 *
 * @author Kevin Bourrillion
 * @author Mike Bostock
 * @author Isaac Shum
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Maps {
  private Maps() {}

  private enum EntryFunction implements Function<Entry<?, ?>, @Nullable Object> {

    assertTrue(entries.contains(Maps.immutableEntry("a", true)));
    assertTrue(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("b", null)));
    assertTrue(
        entries.contains(Maps.<@Nullable String, @Nullable Boolean>immutableEntry(null, null)));

    assertFalse(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("c", null)));

    Map<C, V> row = Maps.safeGet(rowMap(), rowKey);
    return row != null && Maps.safeContainsKey(row, columnKey);
  }

  @Override
  @CheckForNull
  public V get(@CheckForNull Object rowKey, @CheckForNull Object columnKey) {
    Map<C, V> row = Maps.safeGet(rowMap(), rowKey);
    return (row == null) ? null : Maps.safeGet(row, columnKey);
  }

  @Override

                    Map<String, String> map = Maps.newHashMap();
                    putEntries(map, entries);
                    map.putAll(ENTRIES_TO_FILTER);
                    map = Maps.filterEntries(map, FILTER_ENTRIES_1);
                    return Maps.filterEntries(map, FILTER_ENTRIES_2);
                  }
                })
            .named("Maps.filterEntries[Maps.filterEntries[Map, Predicate], Predicate]")

    assertTrue(entries.contains(Maps.immutableEntry("a", true)));
    assertTrue(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("b", null)));
    assertTrue(
        entries.contains(Maps.<@Nullable String, @Nullable Boolean>immutableEntry(null, null)));

    assertFalse(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("c", null)));

                    Map<String, String> map = Maps.newHashMap();
                    putEntries(map, entries);
                    map.putAll(ENTRIES_TO_FILTER);
                    map = Maps.filterEntries(map, FILTER_ENTRIES_1);
                    return Maps.filterEntries(map, FILTER_ENTRIES_2);
                  }
                })
            .named("Maps.filterEntries[Maps.filterEntries[Map, Predicate], Predicate]")

    assertFalse(entries.remove((Object) 4.5));
    assertFalse(entries.contains(Maps.immutableEntry("foo", Collections.singletonList(1))));
    assertFalse(entries.remove(Maps.immutableEntry("foo", Collections.singletonList(1))));
    assertFalse(entries.contains(Maps.immutableEntry("foo", Sets.newLinkedHashSet(asList(1, 2)))));
    assertFalse(entries.remove(Maps.immutableEntry("foo", Sets.newLinkedHashSet(asList(1, 2)))));

    assertEquals(Maps.immutableEntry("foo", 5), entryIterator.next());
    assertEquals(Maps.immutableEntry("bar", 4), entryIterator.next());
    assertEquals(Maps.immutableEntry("foo", 3), entryIterator.next());
    assertEquals(Maps.immutableEntry("cow", 2), entryIterator.next());
    assertEquals(Maps.immutableEntry("bar", 1), entryIterator.next());

    assertTrue(entries.contains(Maps.immutableEntry("a", true)));
    assertTrue(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("b", null)));
    assertTrue(
        entries.contains(Maps.<@Nullable String, @Nullable Boolean>immutableEntry(null, null)));

    assertFalse(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("c", null)));