What are some examples of CountdownLatch in Java?

Can you explain what a CountdownLatch is in Java?

Sure! A CountdownLatch is a synchronization aid that allows one or more threads to wait until a set of operations being performed in other threads completes.

How do I use CountdownLatch in my Java program?

You can create a CountdownLatch by specifying the number of threads to wait for. Use the await() method to block the current thread until the count reaches zero.

Can you provide a code example?

Absolutely! Here's a simple example:

import java.util.concurrent.CountDownLatch;

public class CountdownLatchExample {
    public static void main(String[] args) throws InterruptedException {
        CountDownLatch latch = new CountDownLatch(3);

        for (int i = 0; i < 3; i++) {
            new Thread(new Worker(latch)).start();
        }

        latch.await(); // Wait for all threads to finish
        System.out.println("All workers are done!");
    }
}

class Worker implements Runnable {
    private final CountDownLatch latch;

    Worker(CountDownLatch latch) {
        this.latch = latch;
    }

    public void run() {
        try {
            // Simulate work
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            latch.countDown(); // Decrement the count
        }
    }
}

What happens if the count never reaches zero?

If the count never reaches zero, the thread that called await() will remain blocked indefinitely, which can lead to a deadlock situation.