code: public int lastIndexIn(CharSequence sequence) {
      for (int i = sequence.length() - 1; i >= 0; i--) {
        if (matches(sequence.charAt(i))) {
          return i;
        }
      }
      return -1;
    }
docs: Returns the index of the last matching BMP character in a character sequence, or {@code -1} if
  no matching character is present.
  
  <p>The default implementation iterates over the sequence in reverse order calling {@link
  #matches} for each character.
  
  @param sequence the character sequence to examine from the end
  @return an index, or {@code -1} if no character matches