Java_util_toHex

public String toHex(byte buffer[]) {
        StringBuffer sb = new StringBuffer();
        String s = null;
        for (int i = 0; i < buffer.length; i++) {
            s = Integer.toHexString((int) buffer[i] & 0xff);
            if (s.length() < 2) {
                sb.append('0');
            }
            sb.append(s);
        }
        return sb.toString();
    }