static variable in java class

In java, a static variable in class is shared among all instances(objects).

/**
 * @author lautturi.com 
 * Java example: static variable in java class
 */

import java.util.*;
class Ad{
	String text;
	int id;
	private static int count = 0;
	
	public Ad(String string) {
		text = string;
		count++;
		id = count;
	}
	public static int getCount() {
		return count;
	}
	public void displayAd() {
		System.out.println(id+" " +text);
	}
}
public class Lautturi {
	public static void main(String[] args) {
		Ad ad1 = new Ad("impossible is nothing.");
		Ad ad2 = new Ad("just do it");
		
		ad1.displayAd();
		ad2.displayAd();
//		System.out.println("count:"+ad1.getCount()); // public int getCount() {
//		System.out.println("count:"+ad2.getCount());
		System.out.println("count:"+Ad.getCount());
	}
}

output:

1 impossible is nothing.
2 just do it
count:2