编写测试程序，按照接口回调规则，通过Animal接口调用Pig和Dog的speak()方法。

编写测试程序，按照接口回调规则，通过Animal接口调用Pig和Dog的speak()方法。

package Test_;

/**
 * @author yjx
 * @version 1.0
 */
public class Test4 {
    public static void main(String[] args) {
             speak(new Dog());
             speak(new Pig());
    }
    public static void speak(Animal animal){
        animal.speak();
    }
}
interface Animal{
    void speak();
}
class Pig implements Animal{public void speak(){
    System.out.println("pig is speaking");
}}
class Dog implements Animal{public void speak(){
    System.out.println("dog is speaking");
}}

示例代码如下。

public interface Animal {
    void speak();
}

public class Pig implements Animal{
    @Override
    public void speak() {
        System.out.println("heng...heng...");
    }
}

public class Dog implements Animal {
    @Override
    public void speak() {
        System.out.println("wang...wang...");
    }
}

public class Test {

    public static void main(String[] args) {
        Animal animal = new Dog();
        animal.speak();
    }
}