java的"引用传递"

package shishi.zhizhen;

public class ZY {
    public static void main(String[] args) {
        A a1 = new A();
        A a2 = new A();

        System.out.println("a1: " + a1.toString());
        System.out.println("a2: " + a2.toString());
        System.out.println("-----------------------");

        A a3 = new A();
        a2 = a3;        // 见下方
        System.out.println("a3: "+a3.toString());
        System.out.println("a1: " + a1.toString());
        System.out.println("a2: " + a2.toString());
    }

}

// 随便一个类
class A{
}

这里不管说a2的地址变了，还是赋值成了a3的引用,a2代表的其实就是a3(我觉得明白这一点就ok了)