// staticchecking/dr/DogsAndRobots.java

// (c)2021 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

// {java staticchecking.dr.DogsAndRobots}

package staticchecking.dr;

interface Speaks { void talk(); }

class Dog implements Speaks {

@Override public void talk() {

System.out.println("Woof!");

}

public void reproduce() { }

}

class Robot implements Speaks {

@Override public void talk() {

System.out.println("Click!");

}

public void oilChange() { }

}

class Communicate {

public static <T extends Speaks>

void speak(T speaker) {

speaker.talk();

}

}

public class DogsAndRobots {

public static void main(String[] args) {

Dog d = new Dog();

Robot r = new Robot();

Communicate.speak(d);

Communicate.speak(r);

}

}

/* Output:

Woof!

Click!

*/