檢視 SCJP 1.6版考題 226 的原始碼

<br>Which two statements are true? (Choose two.) 
<br>&nbsp; A. It is possible to synchronize static methods. 
<br>&nbsp; B. When a thread has yielded as a result of yield(), it releases its locks. 
<br>&nbsp; C. When a thread is sleeping as a result of sleep(), it releases its locks. 
<br>&nbsp; D. The Object.wait() method can be invoked only from a synchronized context. 
<br>&nbsp; E. The Thread.sleep() method can be invoked only from a synchronized context. 
<br>&nbsp; F. When the thread scheduler receives a notify() request, and notifies a thread, that thread immediately releases its lock. 
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<span style="font-size:medium;">解答</span>

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<span style="font-size: medium;">Ans: A D   </span>

<span style="font-size:medium;"> 解說:
&nbsp;A. It is possible to synchronize static methods. 對靜態的方法同步是可能的。 
<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; B. When a thread has yielded as a result of yield(), it releases its locks. <br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;當一個執行緒執行yield方法時，會釋放他的locks。 <br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;(執行yield不需要取得與釋放locks) 
<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;C. When a thread is sleeping as a result of sleep(), it releases its locks. <br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;當一個執行緒執行sleep()，會釋放其locks… <br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;(執行sleep不需要取得與釋放locks) 
<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; D. The Object.wait() method can be invoked only from a synchronized context. <br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;一個物件的wait方法只能由同步的本文中被叫用。 
<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;E. The Thread.sleep() method can be invoked only from a synchronized context. 
<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Thread.sleep()方法只能由同步的本文中被叫用。 
<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;(不必) 
<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;F. When the thread scheduler receives a notify() request, and notifies a thread, that thread immediately releases its lock. 
<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 當執行緒的排班器收到一個notify的通知，被通知的執行緒會立刻釋放其lock <br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; (排班器是負責從runnable狀態中的執行緒找一個進入cpu，不會去處理在wait狀態中的執行緒) 
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{{SCJP 1.6版考題講解}}