cannot find IP

Launcher.java

import java.net.InetAddress;
import java.net.UnknownHostException;

public class Launcher {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		InetAddress addr;
		try {
			addr = InetAddress.getLocalHost();
			String host = addr.getHostAddress();
			System.out.println(host);
		} catch (UnknownHostException e) {
			throw new InstantiationError("cannot find hub ip");
		}

	}

}