Java Multithreading and Parallel Programming Masterclass - Introducing the ThreadPoolExecutor Class

This video tutorial covers the ThreadPoolExecutor class in Java, focusing on its parameters, such as work queue and core pool size, and how to create and manage thread pools. It explains how to submit tasks using execute and submit methods, handle task results with Future, and shut down thread pools gracefully or forcefully. The tutorial also discusses configuring core pool size and pre-starting threads for efficient task management.

What is the primary role of the work queue in a Thread Pool Executor?

• To monitor thread health

• To hold tasks before they are executed by worker threads

• To store completed tasks

• To manage thread priorities

What happens when the work queue is full and all worker threads are busy?

• The thread pool throws an exception

• The thread pool shuts down

• The thread pool expands up to the maximum pool size

• The thread pool ignores new tasks

Which method is used to submit a task that does not return a result?

• submit()

• call()

• run()

• execute()

What is a Callable in Java?

• A task that manages thread priorities

• A task that returns a result and may throw an exception

• A task that does not return a result

• A task that runs indefinitely

How can you retrieve the result of a task submitted to a thread pool?

• By using the run() method

• By using the get() method on a Future object

• By calling the execute() method

• By checking the task's status

What does the shutdown() method do in a thread pool?

• Increases the number of threads

• Clears the work queue

• Immediately stops all tasks and threads

• Stops accepting new tasks and waits for current tasks to finish

What is the difference between shutdown() and shutdownNow()?

• shutdown() clears the queue, shutdownNow() does not

• shutdown() increases threads, shutdownNow() decreases them

• shutdown() waits for tasks to complete, shutdownNow() interrupts them

• shutdown() is forceful, shutdownNow() is graceful

What is the purpose of pre-starting core threads in a thread pool?

• To ensure threads are ready before tasks arrive

• To decrease the number of threads

• To reduce memory usage

• To increase task execution time

What does the awaitTermination() method do?

• It blocks until all tasks are completed or the timeout occurs

• It immediately stops all tasks

• It increases the thread pool size

• It clears the work queue

Why might you choose to use the shutdownNow() method?

• To gracefully complete all tasks

• To decrease the core pool size

• To immediately stop all tasks and retrieve pending tasks

• To increase the number of worker threads