Method copyOf

guava/src/com/google/common/collect/ImmutableBiMap.java:534–545

Returns an immutable bimap containing the same entries as map. If map somehow contains entries with duplicate keys (for example, if it is a SortedMap whose comparator is not consistent with equals ), the results of this method are undefined. The returned {@code BiMa

(Map<? extends K, ? extends V> map)

   * @throws NullPointerException if any key or value in {@code map} is null
   */
  public static <K, V> ImmutableBiMap<K, V> copyOf(Map<? extends K, ? extends V> map) {
    if (map instanceof ImmutableBiMap) {
      @SuppressWarnings("unchecked") // safe since map is not writable
      ImmutableBiMap<K, V> bimap = (ImmutableBiMap<K, V>) map;
      // TODO(lowasser): if we need to make a copy of a BiMap because the
      // forward map is a view, don't make a copy of the non-view delegate map
      if (!bimap.isPartialView()) {
        return bimap;
      }
    }
    return copyOf(map.entrySet());
  }

  /**
   * Returns an immutable bimap containing the given entries. The returned bimap iterates over