public static IPv6Network getByAddress(String address, int mask) throws NetworkException {
        if ((mask < 0) || (mask > 128)) {
            throw new InvalidAddressException(String.format("'%d' is not a valid IPv6 mask.", mask));
        }
        try {
            return new IPv6Network(new BigInteger(Inet6Address.getByName(address).getAddress()), BigInteger.valueOf(mask));
        } catch (UnknownHostException ex) {
            throw new InvalidAddressException(String.format("%s is not a valid address", address));
        }
    }