package no1;
public class Duotai {
    public static void mian(String args[]){
        Father father=new Son1();
        father.a();
    }
}
class Father{
    public void a(){
        b();
    }
    public void b(){
        System.out.println("father");
    }
}
class Son1 extends Father{
    public void a(){
        System.out.println("重写a()方法");
    }
}
class Son2 extends Father{
    public void b(){
        System.out.println("重写b()方法");
    }
}