private static String toHex(byte[] ary) {        final String hex = "0123456789ABCDEF";        String ret = "";        for (int i = 0; i < ary.length; i++) {            ret += hex.charAt((ary[i] >> 4) & 0xf);            ret += hex.charAt(ary[i] & 0xf);        }        return ret;    }