package holding;

/**

* RUN:

* javac holding/GenericsAndUpcasting.java && java holding.GenericsAndUpcasting

* OUTPUT:

* GrannySmith

* Gala

* Fuji

* Braeburn

*/

import java.util.*;

public class GenericsAndUpcasting {

public static void main(String[] args) {

ArrayList<Apple> apples = new ArrayList<Apple>();

apples.add(new GrannySmith());

apples.add(new Gala());

apples.add(new Fuji());

apples.add(new Braeburn());

for (Apple c : apples) {

System.out.println(c);

}

}

}

class GrannySmith extends Apple { }

class Gala extends Apple { }

class Fuji extends Apple { }

class Braeburn extends Apple { }

class Apple {

private static long counter;

private final long id = counter++;

public long id() { return id; }

public String toString() { return getClass().getSimpleName(); }

}