code: public static String toLowerCase(CharSequence chars) {
      if (chars instanceof String) {
        return toLowerCase((String) chars);
      }
      int length = chars.length();
      StringBuilder builder = new StringBuilder(length);
      for (int i = 0; i < length; i++) {
        builder.append(toLowerCase(chars.charAt(i)));
      }
      return builder.toString();
    }
docs: Returns a copy of the input character sequence in which all {@linkplain #isUpperCase(char)
  uppercase ASCII characters} have been converted to lowercase. All other characters are copied
  without modification.
  
  @param chars the chars
  @return the string
  @since 14.0