How do I make the method return type generic?

Question

Consider this example (typical in OOP books):

I have an Animal class, where each Animal can have many friends.
And subclasses like

Answer 1

I know this is a completely different thing that the one asked. Another way of resolving this would be reflection. I mean, this does not take the benefit from Generics, but it lets you emulate, in some way, the behavior you want to perform (make a dog bark, make a duck quack, etc.) without taking care of type casting:

import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;

abstract class AnimalExample {
    private Map> friends = new HashMap>();
    private Map theFriends = new HashMap();

    public void addFriend(String name, Object friend){
        friends.put(name,friend.getClass());
        theFriends.put(name, friend);
    }

    public void makeMyFriendSpeak(String name){
        try {
            friends.get(name).getMethod("speak").invoke(theFriends.get(name));
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        }
    } 

    public abstract void speak ();
};

class Dog extends Animal {
    public void speak () {
        System.out.println("woof!");
    }
}

class Duck extends Animal {
    public void speak () {
        System.out.println("quack!");
    }
}

class Cat extends Animal {
    public void speak () {
        System.out.println("miauu!");
    }
}

public class AnimalExample {

    public static void main (String [] args) {

        Cat felix = new Cat ();
        felix.addFriend("Spike", new Dog());
        felix.addFriend("Donald", new Duck());
        felix.makeMyFriendSpeak("Spike");
        felix.makeMyFriendSpeak("Donald");

    }

}