What are the differences between semaphores and locks in Java?

What are the differences between semaphores and locks in Java?

Semaphores and locks are both synchronization mechanisms in Java, but they serve different purposes. A lock allows only one thread to access a resource at a time, while a semaphore can allow multiple threads to access a resource, up to a specified limit.

Can you explain how semaphores work in Java?

Sure! A semaphore maintains a set of permits. Threads can acquire a permit before accessing a resource and release it afterward. If no permits are available, the thread will block until one becomes available.

What about locks? How do they differ in implementation?

Locks in Java, like ReentrantLock, provide exclusive access to a resource. They can be more flexible than synchronized blocks, allowing features like try-lock and timed lock, which semaphores do not offer.

Are there any performance differences between using semaphores and locks?

Yes, performance can vary based on the use case. Locks can be more efficient for exclusive access, while semaphores are better for controlling access to a limited number of resources.