SCJP題庫第243題

 

Given that Triangle implements Runnable, and:

 

31. void go() throws Exception{

32.    Thread t = new Thread(new Triangle());

33.    t.start();

34.    for(int x=1; x<100000; x++){

35.     //insert code here

36.    if(x%100 == 0) System.out.print("g");

37. }}

38. public void run(){

39.   try{

40.     for(int x=1; x<100000; x++){

41.       //insert the same code here

42.       if(x%100 == 0) System.out.print("t");

43.     }

44. }catch(Exception e){}

45.}

Which two statements, inserted independently at both lines 35 and 41, tend to allow both threads to temporarily pause and allow the other thread to execute? (Choose two.)

A. Thread.wait();

B. Thread.join();

C. Thread.yield();

D. Thread.sleep(1);

E. Thread.notify();

Ans: CD

解說:在第35行和41行插入那二個程式敘述，可以使得二條執行暫時性地停止並允許其他執行緖可以執行？


yield的退讓的意思，一旦下yield，立刻退出CPU，進入runable狀態。


sleep是睡眠一段時間(也是離開CPU，但確保多少時間後才能進runable的狀態).。