Java threads: Which of the following will directly cause a thread to cease executing (stop running) at that moment?
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Await()
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Bnotify()
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Cnotifyall()
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Dexits synchronized code
Answer
Correct Answer: wait()
Explanation
Introduction / Context:Java threads change state based on specific primitives. Knowing which calls block the current thread is critical for correct synchronization.
Given Data / Assumptions:
- The thread owns a monitor when calling
wait(). - We are comparing the immediate effect on the calling thread's execution.
Concept / Approach:wait() immediately causes the current thread to release the monitor and enter the WAITING (or TIMED_WAITING with timeout) state. In effect, it stops the current thread from executing until notified/timeout.
Step-by-Step Solution:
1) The calling thread is in synchronized code holding a monitor.2)wait() → releases the monitor and suspends the thread.3) Later, a notify/notifyAll or timeout can move the thread to contend for the monitor again.Verification / Alternative check:By contrast, notify() and notifyAll() affect other waiting threads, not the calling thread.
Why Other Options Are Wrong:
notify(),notifyAll()→ do not block the caller; they wake others.- Exiting synchronized code → simply releases the lock and continues running; it does not block or stop the thread.
Common Pitfalls:Confusing wait() (blocking caller) with sleep() (also blocks caller but without monitor semantics) and with notify()/notifyAll() (do not block caller).
Final Answer:wait()