validate ip address with regex in java

/**
 * @author lautturi.com 
 * Java example: how to validate ip address in java
 */


import java.util.*;
import java.util.regex.*;

public class Lautturi {

	public static void main(String[] args) {
		String ip = "192.168.1.100";
		String invalidIP = "192.168.1.256";
		
		String ipAddressRegex = "^(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])("+Pattern.quote(".")+"(?!$)|$)){4}$";
		Pattern p = Pattern.compile(ipAddressRegex);
		Matcher m = p.matcher(ip);
//		Matcher m = p.matcher(invalidIP);
		Boolean b = m.matches();     
		if(b) {
			System.out.println("It's a valid ip");
		}
	}
}

output:

It's a valid ip