Question

This is my below code and I want to catch the exception if any IPV6 address is passed. Any idea how it can be done in my code?

private static boolean validateAnIpAddress(String ipAddr) {  

     InetAddress address = null;
     boolean isIPv4;

        try {
            address = InetAddress.getByName(ipAddr);
            isIPv4 = address.getHostAddress().equals(ipAddr) && address instanceof Inet4Address;
        } catch (UnknownHostException e) {
            getLogger().log(LogLevel.ERROR, e.getMessage());
            //return false;
            isIPv4 = false;
        }

        return isIPv4;

     }

Answer 1

try
{
    address = InetAddress.getByName(ipAddr);

    boolean isIPv6 = address instanceof Inet6Address;
    if (isIPv6)
        throw new UnknownHostException("IPv6 Address");

    isIPv4 = address.getHostAddress().equals(ipAddr) && address instanceof Inet4Address;
}

By checking if address is an Inet6Address type, you can throw the exception inside the try block and therefore triggering your catch block.