import java.util.*;



public abstract class Animal {
    private String name;
    abstract void showInfo();
    abstract void act();
   
}



public class Cat extends Animal {
    void showInfo(){
        System.out.println("我是一只猫，");
    }
    void act(){
        System.out.println("我将表演猫步");
    }
}


public abstract class Dog extends Animal{
    void showInfo(){
        System.out.println("我是一只狗");
    }
    void act(){
        System.out.println("我将表演双脚站立行走！");
    }

}




public abstract class Bird extends Animal {
    void showInfo(){
        System.out.println("我是一只鸟");
    }
    void act(){
        System.out.println("我将表演唱歌");
    }
}


public class zoo {

    public static void main(String[] args) {
        
        
        Cat cat1 =new Cat();
        Bird bird1 =new Bird();//Cannot instantiate the type Bird
        Dog dog1=new Dog();//Cannot instantiate the type Dog
        
    }

}

为什么注释的两行，会出来后面的错误？

我已经知道了，是我在Cat和Bird类前加了abstract~

抽象类不能实例化