What are best practices for working with ReentrantLock?

When working with ReentrantLock in Java, it's essential to follow best practices to ensure thread safety, maximize performance, and prevent common pitfalls such as deadlocks. Here are some best practices:

• Prefer ReentrantLock over synchronized: While synchronized blocks are easier to read, ReentrantLock offers more flexibility such as timed locking and the ability to interrupt threads waiting for a lock.
• Always use try-finally: Always ensure that you call unlock() within a finally block to prevent deadlocks caused by exceptions.
• Use tryLock: Consider using tryLock() to avoid blocking indefinitely, especially in scenarios where the locked resource may not be critical for the current operation.
• Understand lock fairness: When creating a ReentrantLock, you can specify whether it should use a fair ordering policy. Fair locks can reduce thread starvation, but may incur performance penalties.
• Avoid lock contention: Design your application to minimize contention by reducing the time locks are held and splitting large tasks into smaller ones where possible.

Example Code

import java.util.concurrent.locks.ReentrantLock;

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

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

    public void tryLockExample() {
        if (lock.tryLock()) {
            try {
                // Perform operation
            } finally {
                lock.unlock();
            }
        } else {
            // Handle the case when lock is not acquired
        }
    }
}