IPv4 - represents a Network Interface address

InternetProtocol.java

import java.net.Inet4Address;
import java.net.UnknownHostException;

public class InternetProtocol {

	public static void main(String[] args) throws UnknownHostException {
		representsInet4Address();
	}

	private static void representsInet4Address() throws UnknownHostException {
		System.out.println(
				Inet4Address.getByName(
						Inet4Address.getLocalHost()
						.getCanonicalHostName())
				.getHostAddress());
	}

}

IPv4.java

import java.net.InterfaceAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.Enumeration;

public class IPv4 {

	public static void main(String[] args) throws SocketException {
		getIPv4();
	}

	private static void getIPv4() throws SocketException {
		Enumeration<NetworkInterface> nis = NetworkInterface.getNetworkInterfaces();
        NetworkInterface ni;
        while (nis.hasMoreElements()) {
            ni = nis.nextElement();
            if (!ni.isLoopback() && ni.isUp()) {
                System.out.println(ni);
                for (InterfaceAddress ia : ni.getInterfaceAddresses()) {
                    if (ia.getAddress().getAddress().length == 4) {
                        System.out.println(ia.getAddress());
                    }
                }
            }
        }
	}

}