}

  /**
   * Delegates to {@link Map#get}. Returns {@code null} on {@code ClassCastException} and {@code
   * NullPointerException}.
   */
  static <V extends @Nullable Object> @Nullable V safeGet(Map<?, V> map, @Nullable Object key) {
    checkNotNull(map);
    try {
      return map.get(key);
    } catch (ClassCastException | NullPointerException e) {
      return null;
    }
  }

  /**

  }

  /**
   * Delegates to {@link Map#get}. Returns {@code null} on {@code ClassCastException} and {@code
   * NullPointerException}.
   */
  static <V extends @Nullable Object> @Nullable V safeGet(Map<?, V> map, @Nullable Object key) {
    checkNotNull(map);
    try {
      return map.get(key);
    } catch (ClassCastException | NullPointerException e) {
      return null;
    }
  }

  /**

     * well-tested. A purist would object to this, but what can I say, we're dirty cheaters.
     */
    map.put(Integer.class, new Integer(5));
    assertThrows(ClassCastException.class, () -> map.put(Double.class, new Long(42)));
    // Won't compile: map.put(String.class, "x");
  }

  public void testPutAndGetInstance() {
    assertThat(map.putInstance(Integer.class, new Integer(5))).isNull();