mac address

NetUtil.java

// generate random MAC address
public static String randomMACAddress() {
    Random rand = new Random();
    byte[] macAddr = new byte[6];
    rand.nextBytes(macAddr);

    macAddr[0] = (byte) (macAddr[0] & (byte) 254);

    StringBuilder sb = new StringBuilder(18);
    for (byte b : macAddr) {
        if (sb.length() > 0)
            sb.append(":");

        sb.append(String.format("%02x", b));
    }
    return sb.toString();
}

// check MAC
public static boolean checkMacAvailable(String macAddress) {
    String patternMac = "^[a-f0-9]{2}(:[a-f0-9]{2}){5}$";
    return Pattern.compile(patternMac).matcher(macAddress).find();
}