Converter<Long, String> reverseConverter = STR_TO_LONG.reverse();

    assertThat(reverseConverter.convert(LONG_VAL)).isEqualTo(STR_VAL);
    assertEquals(LONG_VAL, reverseConverter.reverse().convert(STR_VAL));

    Iterable<String> convertedValues = reverseConverter.convertAll(LONGS);
    assertEquals(STRINGS, ImmutableList.copyOf(convertedValues));

    assertThat(reverseConverter.reverse()).isSameInstanceAs(STR_TO_LONG);

  public Converter<B, A> reverse() {
    Converter<B, A> result = reverse;
    return (result == null) ? reverse = new ReverseConverter<>(this) : result;
  }

  private static final class ReverseConverter<A, B> extends Converter<B, A>
      implements Serializable {
    final Converter<A, B> original;

    ReverseConverter(Converter<A, B> original) {
      this.original = original;
    }

    /*

  public Converter<B, A> reverse() {
    Converter<B, A> result = reverse;
    return (result == null) ? reverse = new ReverseConverter<>(this) : result;
  }

  private static final class ReverseConverter<A, B> extends Converter<B, A>
      implements Serializable {
    final Converter<A, B> original;

    ReverseConverter(Converter<A, B> original) {
      this.original = original;
    }

    /*