作者zheng2010 (自我催眠)
看板java
标题[问题] 物件与多执行绪的问题
时间Sat May 18 00:13:32 2013
各位前辈们好，
在下面那简单的程式码中
s会重复被assign，所以
我预期的输出结果是
s1=this is obj1
s2=this is obj2
s2=this is obj2 <--- Main can Access
s2=this is obj2 <--- Main can Access
s2=this is obj2 <--- Main can Access
s2=this is obj2 <--- Main can Access
s2=this is obj2 <--- Main can Access
s2=this is obj2 <--- Main can Access
但是因为字串是由thread来印的
所以实际上的输出如下
s1=this is obj1
s2=this is obj2
s1=this is obj1
s2=this is obj2 <--- Main can Access
s1=this is obj1
s2=this is obj2 <--- Main can Access
s1=this is obj1
s2=this is obj2 <--- Main can Access
s1=this is obj1
s2=this is obj2 <--- Main can Access
也就是说第一个物件还是存在着?
照理说不是进行第二次的s = new CAR("s2=this is obj2")後
GC就会去把access不到的记忆体清掉吗，那为什麽还是会一直印出s1=.....
还是说是因为thread的关系?(thread 负责印出字串)
谢谢
---------------程式码-----------------------------
public class Game{
static CAR s;
public static void main(String []args){
s = new CAR("s1=this is obj1");
s = new CAR("s2=this is obj2");
try{
Thread.sleep(2000);
}catch(Exception e)
{
}
s.x+=" <--- Main can Access";
}
}
class CAR {
CAR(String s)
{
x=s;
Thread thread1 = new Thread(aa);
thread1.start();
}
public String x;
private Runnable aa= new Runnable(){
@Override
public void run() {
while(true)
{
System.out.println(x);
try{
Thread.sleep(1000);
}catch(Exception e)
{
}
}
}//run
};
}
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◆ From: 114.35.228.73
1F：推 PsMonkey:只是 s 没有指向第一个 car，不代表第一个 car 没人 ref 05/18 00:21
2F：推 Elohim123:乍看起来是因为每次在做new CAR()时constructor里面 05/18 00:22
3F：→ Elohim123:都会去做thread1.start()这样 ? 05/18 00:23
4F：→ zheng2010:可是thread1也是物件的一部分，所以物件自己ref自己? 05/18 00:30
5F：→ asilzheng:没说过 GC 会马上动作吧? 05/18 00:37
6F：推 PsMonkey:看一下 Thread.init() 吧 05/18 00:42
7F：→ zheng2010:回a大 如果第一个car还有人ref GC应该就不会清掉它吧? 05/18 00:56
8F：→ cha122977:还有人ref阿 不然怎麽印出来的? 05/18 04:50