package com.sf; public class Main { // 三个重载方法,参数类型分别为以上三种类型 static void sayHello(Human human) { System.out.println("human say Hello"); } static void sayHello(Man man) { System.out.println("man say Hello"); } static void sayHello(Woman woman) { System.out.println("woman say Hello"); } public static void main(String[] args) { Human man = new Man(); Human woman = new Woman(); sayHello(man); sayHello(woman); } } // 声明一个父类 两个子类 class Human { } class Man extends Human { } class Woman extends Human { }