} else if (base64Alphabet[octect] == -1) {
} else if (octect < 0 || base64Alphabet[octect] == -1) {
    private static boolean isBase64(byte octect) {        if (octect == PAD) {            return true;        } else if (base64Alphabet[octect] == -1) {            return false;        } else {            return true;        }    }