instanceof关键字问题

Question

public class InstanceofKeyWordDemo{ public static void main (String[] args){ Person man = new Men(); say(man); Person women = new Women(); say(women); } public static void say(Person p){ p.say(); //判断p对象是否为Women的实例 if (p instanceof Women){ Women women = (Women)p; women.buy(); } }}abstract class Person{ private String name; public void setName(String name){ this.name = name; } public String getName(){ return name; } public abstract void say();//抽象方法}class Men extends Person{ public void say(){ System.out.println("我是纯爷们!"); }}class Women extends Person{ public void say(){ System.out.println("我是女神经!"); } //本类扩展方法 public void buy(){ System.out.println("是时候改变一下GDP指数了!"); }}运行结果为：我是纯爷们!Exception in thread "main" 我是女神经!java.lang.NoSuchMethodError: Women.buy()V at InstanceofKeyWordDemo.say(InstanceofKeyWordDemo.java:17) at InstanceofKeyWordDemo.main(InstanceofKeyWordDemo.java:10)大神们帮我看看，哪里出错了，谢谢！！！

Answer 1

复制运行了下，没问题的，楼主clean一下再运行吧。

Answer 2

我的错误是这样的

Answer 3

貌似没错啊