What are Java Reentrant Locks and how do they work?

What are Java Reentrant Locks and how do they work?

Java Reentrant Locks are synchronization primitives that allow threads to safely access shared resources. They enable a thread to acquire a lock multiple times without causing a deadlock.

Can you explain the difference between Reentrant Locks and synchronized blocks?

Sure! Reentrant Locks provide more flexibility than synchronized blocks. They allow for features like try-lock, timed lock, and the ability to interrupt a thread waiting for a lock.

When should I use Reentrant Locks instead of synchronized blocks?

Use Reentrant Locks when you need advanced locking features, such as fairness policies or the ability to interrupt threads. For simpler cases, synchronized blocks are often sufficient.

Are there any performance considerations when using Reentrant Locks?

Yes, Reentrant Locks can introduce overhead due to their advanced features. In high-contention scenarios, they may perform worse than synchronized blocks.

Can you provide a code example of using a Reentrant Lock?

Certainly! Here's a simple example:

import java.util.concurrent.locks.ReentrantLock;

public class Example {
    private final ReentrantLock lock = new ReentrantLock();

    public void safeMethod() {
        lock.lock();
        try {
            // critical section
        } finally {
            lock.unlock();
        }
    }
}