Core Java Interview Questions and Answers
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Ques 151. Whats the difference between notify() and notifyAll()?
notify() is used to unblock one waiting thread; notifyAll() is used to unblock all of them. Using notify() is preferable (for efficiency) when only one blocked thread can benefit from the change (for example, when freeing a buffer back into a pool). notifyAll() is necessary (for correctness) if multiple threads should resume (for example, when releasing a 'writer'?? lock on a file might permit all 'readers'?? to resume).
Ques 152. Can a lock be acquired on a class?
Yes, a lock can be acquired on a class. This lock is acquired on the class's Class object.
Ques 153. What state does a thread enter when it terminates its processing?
When a thread terminates its processing, it enters the dead state.
Ques 154. What is a task's priority and how is it used in scheduling?
A task's priority is an integer value that identifies the relative order in which it should be executed with respect to other tasks. The scheduler attempts to schedule higher priority tasks before lower priority tasks.
Ques 155. What is a daemon thread?
These are the threads which can run without user intervention. The JVM can exit when there are daemon thread by killing them abruptly.
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