NetworkInterface.getNetworkInterfaces()

import java.net.*;
import java.util.*;
 
public class Test{
	public static void main(String[] args) {
		Test t = new Test();
		try{
			Enumeration e = NetworkInterface.getNetworkInterfaces();
			while (e.hasMoreElements()) {
			     System.out.println(e.nextElement());
			}
		}catch(Exception e){
		}
	}
}

import java.net.*;
public class Test{
	public static void main(String[] args) {
	try{
		String ip=InetAddress.getLocalHost().getHostAddress();
		System.out.println(ip);
	}catch(Exception e){
		}
	}
}