Java多态的优势和弊端

1.

public class text {
    public static void main(String[] args) {
        animal d=new dog();
        d.eat();
       // dog a = (dog) d;//类似强制转换
        //a.lookhome();
       /* if(d instanceof dog){
            dog a=(dog)d;
            a.lookhome();
        }else if(d instanceof cat){
           cat c=(cat) d;
           c.work();
        }else{
            System.out.println("没有这个类型，无法转换");
        }*/
        if(d instanceof dog a){
            a.lookhome();
        }else if(d instanceof cat c){
            c.work();
        }else{
            System.out.println("没有这个类型，无法转换");
        }
    }
}

class animal{
    public void eat(){
        System.out.println("在吃东西");
    }

}
class dog extends animal{
    @Override
    public void eat() {
        System.out.println("狗在吃骨头");
    }


    public void lookhome(){
        System.out.println("狗在看家");
    }
}
class cat extends animal{
    @Override
    public void eat() {
        System.out.println("猫在吃鱼");
    }
    public void work(){
        System.out.println("猫在抓老鼠");
    }
}