* @param <V> the value type of {@link HashMap}
     * @return a new instance of {@link HashMap}
     * @see HashMap#HashMap()
     */
    public static <K, V> HashMap<K, V> newHashMap() {
        return new HashMap<>();
    }

    /**
     * Creates and returns a new instance of {@link HashMap}.
     *
     * @param <K> the key type of {@link HashMap}

    HashMap<Integer, Integer> map = Maps.newHashMap();
    assertEquals(emptyMap(), map);
  }

  public void testHashMapWithInitialMap() {
    Map<String, Integer> original = new TreeMap<>();
    original.put("a", 1);
    original.put("b", 2);
    original.put("c", 3);
    @SuppressWarnings("UseCollectionConstructor") // test of factory method
    HashMap<String, Integer> map = Maps.newHashMap(original);
    assertEquals(original, map);

    HashMap<Integer, Integer> map = Maps.newHashMap();
    assertEquals(emptyMap(), map);
  }

  public void testHashMapWithInitialMap() {
    Map<String, Integer> original = new TreeMap<>();
    original.put("a", 1);
    original.put("b", 2);
    original.put("c", 3);
    @SuppressWarnings("UseCollectionConstructor") // test of factory method
    HashMap<String, Integer> map = Maps.newHashMap(original);
    assertEquals(original, map);