code: static boolean checkStandardUPCEANChecksum(CharSequence s) throws FormatException {
      int length = s.length();
      if (length == 0) {
        return false;
      }
      int check = Character.digit(s.charAt(length - 1), 10);
      return getStandardUPCEANChecksum(s.subSequence(0, length - 1)) == check;
    }
docs: Computes the UPC/EAN checksum on a string of digits, and reports
  whether the checksum is correct or not.
  
  @param s string of digits to check
  @return true iff string of digits passes the UPC/EAN checksum algorithm
  @throws FormatException if the string does not contain only digits