java学习笔记（3）多态

向上转型

class Base
{
public Base(){}
public void fun1(){
fun2();
}
public void fun2(){
System.out.println("base");
}
}

class Child extends Base
{
public Child(){}
public void fun2(){
System.out.println("Child");
}
}

class Test
{
public static void main(String args[]){
Base b = new Child();
b.fun1();//输出Child
}
}