抽象类

package com_black.Abstract;

public abstract class Animal {
    public  abstract void eat();

    //抽象类里可以有具体的方法
    public void sleep(){
        System.out.println("睡觉");
    }
}

package com_black.Abstract;

public class Cat extends Animal {
    @Override
    public void eat(){
        System.out.println("猫吃鱼");
    }
}

package com_black.Abstract;

public class AnimalDemo {
    public static void main(String[] args) {
        Animal a=new Cat();
        a.eat();
        a.sleep();
    }
}