28_多态

08_多态

public class Application {
    public static void main(String[] args) {

        Student s1 = new Student();
        Person s2 = new Student();
        Object s3 = new Student();

        s1.run();//Student run
        s2.run();//Student run
        s1.eat();//Student eat

    }
}

public class Person {
    public void run(){
        System.out.println("person run");
    }
}

public class Student extends Person{

    @Override
    public void run() {
        System.out.println("Student run");
    }
    public void eat(){
        System.out.println("Student eat");
    }
}

小提示

1. 多态是方法的多态，属性没有多态。

2. 多态存在条件：

   1. 有继承关系
   2. 方法需要重写
   3. 父类的引用指向子类对象（Person指向Student）