What is the difference between synchronized and reentrant locks in Java?

What is the difference between synchronized and reentrant locks in Java?

Synchronized locks are built into Java, providing a simple way to control access to a method or block. Reentrant locks, on the other hand, are part of the java.util.concurrent package and offer more flexibility, such as the ability to interrupt threads and try to acquire the lock without blocking.

Can you explain how reentrant locks work?

Reentrant locks allow a thread to acquire the same lock multiple times without causing a deadlock. Each time the lock is acquired, a counter is incremented, and the lock is only released when the counter reaches zero.

When should I use synchronized over reentrant locks?

Use synchronized when you need a simple locking mechanism and don't require advanced features. Reentrant locks are better for complex scenarios where you need more control over thread behavior.

Are there any performance differences between the two?

Yes, reentrant locks can be more performant in high-contention scenarios due to their non-blocking features, but they also introduce more complexity.