public boolean equals(@Nullable Object obj) {
      if (obj instanceof SameByteInstance) {
        SameByteInstance that = (SameByteInstance) obj;
        return i == that.i;
      }
      return false;
    }
  }

  static class SameCharacterInstance {
    private final Character i;

    public SameCharacterInstance(Character i) {
      this.i = checkNotNull(i);