Random MAC address

public String getMacAddress()
    {
        StringBuilder macAddress = new StringBuilder(getRandomHex());
        for (int i = 0; i < 5; i++)
            macAddress.append(":").append(getRandomHex());
        return macAddress.toString();
    }

    private String getRandomHex()
    {
        int random = (int) (Math.random() * 1000);
        if (random > 255)
            random %= 255;

        String hex = Integer.toString(random, 16);
        if (hex.length() == 1)
            hex = "0" + hex;
        return hex;
    }