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Java Concurrency Interview Questions and Answers

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Ques 21. Explain the concept of the CopyOnWriteArrayList class.

CopyOnWriteArrayList is a thread-safe variant of ArrayList in which all mutative operations (add, set, etc.) are implemented by making a fresh copy of the underlying array.

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Ques 22. What is the purpose of the Phaser class in Java?

Phaser is a synchronization barrier that allows a set of threads to wait for each other to reach a common phase before proceeding.

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Ques 23. Explain the concept of the ReadWriteLock interface.

ReadWriteLock provides a pair of associated locks for read and write access, allowing multiple threads to read the data concurrently or a single thread to write it exclusively.

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Ques 24. What is the purpose of the ScheduledExecutorService interface?

ScheduledExecutorService is an extension of ExecutorService that supports delayed and periodic task execution.

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Ques 25. Explain the concept of the BlockingQueue interface.

BlockingQueue is a queue that supports operations that wait for the queue to become non-empty when retrieving an element and wait for space to become available when storing an element.

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