[問題] 物件與多執行緒的問題

看板java作者zheng2010 (自我催眠)時間12年前 (2013/05/18 00:13)推噓3(3推 0噓 5→)

留言8則, 5人參與討論串1/2 (看更多)

各位前輩們好，在下面那簡單的程式碼中 s會重複被assign，所以我預期的輸出結果是 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 但是因為字串是由thread來印的所以實際上的輸出如下 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 也就是說第一個物件還是存在著? 照理說不是進行第二次的s = new CAR("s2=this is obj2")後 GC就會去把access不到的記憶體清掉嗎，那為什麼還是會一直印出s1=..... 還是說是因為thread的關係?(thread 負責印出字串) 謝謝 ---------------程式碼----------------------------- 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 }; } -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 114.35.228.73

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PsMonkey

05/18 00:21, , 1^F

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Elohim123

05/18 00:22, , 2^F

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Elohim123

05/18 00:23, , 3^F

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