java:对象赋值

package exercise;

class Tank
{
    int level;
}

public class Assignment{
    public static void main(String[]args){
        Tank t1=new Tank();
        Tank t2=new Tank();
        
        t1.level=9;
        t2.level=47;
        
        System.out.println("t1.level:"+t1.level+",t2.level:"+t2.level);
        
        t1=t2;
        System.out.println("t1.level:"+t1.level+",t2.level:"+t2.level);
        //when you assign "from one object to another" ,your are actually copying a reference
        //from one place to another.
        //this means that if you say c=d for objects,you end up with both c and d pointing to
        //the object that, originally,only d pointed to .
        
        t1.level=27;
        System.out.println("t1.level:"+t1.level+",t2.level:"+t2.level);
    }
}

输出

t1.level:9,t2.level:47
t1.level:47,t2.level:47
t1.level:27,t2.level:27