java，

java，

Java源代码编写程序：

package com.tt;

public class Main {

    public static void main(String[] args) {
       Dog d = new Dog();
        d.name = "wangcai";
        System.out.print(d);
        Dog d2 = new Dog();
        Dog d3;
        d3 = d;
        d3.name = "dahuang";
        System.out.println(d.name);
    }
}

package com.tt;

/**
 * Created by Administrator on 2015/3/31 0031.
 */
public class Dog {
    public String name;

}