JAVA学习--接口使用方法2（接口间的多态性）

//接口与具体的实现类之间也存在多态性
public class TestInterface {
    
    public static void main(String[] args) {
        Duck d = new Duck();
        TestInterface.test1(d);
        TestInterface.test2(d);
        TestInterface.test3(d);
    }
    
    public static void test1(Runner r){//Runner r = new Duck();
        r.run();//虚拟方法调用
    }
    public static void test2(Swimmer s){//Swimmer s = new Duck();
        s.swim();
    }
    public static void test3(Flier f){//Flier f = new Duck();
        f.fly();
    }
}

interface Runner{
    public abstract void run();
}
interface Swimmer{
    void swim();
}
interface Flier{
    void fly();
}

class Duck implements Runner,Swimmer,Flier{

    @Override
    public void fly() {
        System.out.println("丑小鸭也可以变成白天鹅！");
    }

    @Override
    public void swim() {
        System.out.println("红掌拨清波");
    }

    @Override
    public void run() {
        System.out.println("鸭子屁股扭扭的走路");
    }
    
}