package com.Hanqi2;public class _1 {        public _1()    {            }    public String xingming;        public String renzhong;        public int age;        public _1(String xingming, String renzhong,int age)    {        System.out.println(xingming + "是一个" + renzhong + "," + age + "岁了");    }    //成长    public void chengzhang(int chengzhang)    {        age += chengzhang;        System.out.println(chengzhang + "年后他" + age + "岁了");            }        }

package com.Hanqi2;public class _2 extends _1{    public _2(String xingming,String renzhong,int age)    {        super(xingming,renzhong,age);    }        public _2()    {            }            public void chengzhang(int grew)    {        age += grew;        System.out.println(grew + "yeas ago,he is " + age);            }}

package com.Hanqi2;public class _3 {    public static void main(String[] args) {        // TODO Auto-generated method stub                _1 body = new _1("mading","白种人",25);                body.age = 25;        body.chengzhang(9);                _1 b1 = new _2();                b1.age = 15;        b1.chengzhang(1);                    }}

结果为 :

mading是一个白种人,25岁了

9年后他34岁了

1yeas ago,he is 16