Java CountDownLatch example

CountDownLatch latch = new CountDownLatch(1);
Runtime.getRuntime().addShutdownHook(new Thread(() -> {
    System.out.println("Shutting down");
    latch.countDown();
}));

Executor executor = Executors.newSingleThreadExecutor();
executor.execute(() -> {
    System.out.println("running");
});

try {
    latch.await();
} catch (InterruptedException e) {
    e.printStackTrace();
}

Another example :

public class Manager {
    public static void main(String[] args) throws InterruptedException {
        CountDownLatch countDownLatch = new CountDownLatch(2);
        MyDevTeam teamDevA = new MyDevTeam(countDownLatch, "devA");
        MyDevTeam teamDevB = new MyDevTeam(countDownLatch, "devB");
        teamDevA.start();
        teamDevB.start();
        countDownLatch.await();
        MyQATeam qa = new MyQATeam();
        qa.start();
    }   
}

class MyDevTeam extends Thread {   
    CountDownLatch countDownLatch;
    public MyDevTeam (CountDownLatch countDownLatch, String name) {
        super(name);
        this.countDownLatch = countDownLatch;       
    }   
    @Override
    public void run() {
        System.out.println("Task assigned to development team " + Thread.currentThread().getName());
        try {
                Thread.sleep(2000);
        } catch (InterruptedException ex) {
                ex.printStackTrace();
        }
        System.out.println("Task finished by development team " + Thread.currentThread().getName());
        this.countDownLatch.countDown();
    }
}

class MyQATeam extends Thread {   
    @Override
    public void run() {
        System.out.println("Task assigned to QA team");
        try {
            Thread.sleep(2000);
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        System.out.println("Task finished by QA team");
    }
}

Output : 
Task assigned to development team devB

Task assigned to development team devA

Task finished by development team devB

Task finished by development team devA

Task assigned to QA team

Task finished by QA team