Java – How To check if an IP address is IPv4 or IPv6

This article shows you how to check if an IP address is IPv4 or IPv6 in Java.

package com.bytenota;

import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class IPAddress {
    
    public static boolean isIPv4(String ipAddress) {
        boolean isIPv4 = false;
        
        if (ipAddress != null) {
            try {
                InetAddress inetAddress = InetAddress.getByName(ipAddress);
                isIPv4 = (inetAddress instanceof Inet4Address) && inetAddress.getHostAddress().equals(ipAddress);
            } catch (UnknownHostException ex) {
            }
        }
 
        return isIPv4;
    }
    
    public static boolean isIPv6(String ipAddress) {
        boolean isIPv6 = false;
        
        if (ipAddress != null) {
            try {
                InetAddress inetAddress = InetAddress.getByName(ipAddress);
                isIPv6 = (inetAddress instanceof Inet6Address);
            } catch (UnknownHostException ex) {
            }
        }
 
        return isIPv6;
    }
}

In the above IPAddress class, we have implemented the following methods:

• isIPv4 method: that checks if an IP address is IPv4 or not
• isIPv6 method: that checks if an IP address is IPv6 or not

 
Use the methods:

package com.bytenota;

public class Program {
    
    public static void main(String[] args) {
        String ipAddress = "2001:db8:a0b:12f0::1";
        //String ipAddress = "42.197.20.45";
        
        if (IPAddress.isIPv4(ipAddress)) {
            System.out.println("This is IPv4");
        } else if (IPAddress.isIPv6(ipAddress)) {
            System.out.println("This is IPv6");
        } else {
            System.out.println("Invalid IP address");
        }
    }
}