public static Ip6Prefix valueOf(byte[] address, int prefixLength) {
        return new Ip6Prefix(Ip6Address.valueOf(address), prefixLength);
    }
@Test(expected = NullPointerException.class)
    public void testInvalidValueOfNullAddress() {
        Ip6Address ipAddress;
        Ip6Prefix ipPrefix;

        ipAddress = null;
        ipPrefix = Ip6Prefix.valueOf(ipAddress, 24);
    }