Builder<K, V> combine(Builder<K, V> other) {
      checkNotNull(other);
      entries.addAll(other.entries);
      return this;
    }

    public ImmutableMap<K, V> build() {
      return buildOrThrow();
    }

    private ImmutableMap<K, V> build(boolean throwIfDuplicateKeys) {
      if (valueComparator != null) {
        Collections.sort(

     * will throw an exception if there are duplicate keys. The {@code build()} method will soon be
     * deprecated.
     *
     * @throws IllegalArgumentException if duplicate keys were added
     */
    public ImmutableMap<K, V> build() {
      return buildOrThrow();
    }

    /**

     * will throw an exception if there are duplicate keys. The {@code build()} method will soon be
     * deprecated.
     *
     * @throws IllegalArgumentException if duplicate keys were added
     */
    public ImmutableMap<K, V> build() {
      return buildOrThrow();
    }

    /**