Java Multithreading and Parallel Programming Masterclass - Let's Synchronize Jobs with Semaphores

The video tutorial introduces the concept of Semaphore in Java, comparing it to a lock and explaining its advanced functionalities. It covers how Semaphore can manage multiple threads with permits, allowing more complex synchronization than a lock. The tutorial also demonstrates Semaphore's methods like acquire and release, and provides an example of using Semaphore to limit job submissions in an execution engine.

What is a key difference between a semaphore and a lock in Java?

• A semaphore can have multiple permits, while a lock can only have one.

• A lock can have multiple permits, while a semaphore can only have one.

• Both semaphore and lock can have multiple permits.

• Neither semaphore nor lock can have multiple permits.

Which method in a semaphore is equivalent to the lock method in a lock?

• permit

• release

• acquire

• unlock

What happens when a semaphore's permits reach zero?

• The semaphore will reset.

• The acquire call will block.

• The release call will block.

• The semaphore will throw an exception.

How can a semaphore's permits be increased?

• By calling the release method.

• By calling the acquire method.

• By calling the unlock method.

• By calling the lock method.

What is the purpose of the tryAcquire method in a semaphore?

• To reset the semaphore.

• To acquire permits without blocking.

• To release permits without blocking.

• To acquire all permits at once.

In the provided example, how many jobs can be executed concurrently?

• Four jobs

• Three jobs

• Two jobs

• One job

What happens to the third job in the example when the semaphore has only two permits?

• It waits for a permit to be released.

• It executes immediately.

• It throws an exception.

• It is canceled.