Without CyclicBarrier

public class WithoutCyclicBarrier {

    public static void main(String[] args) {
        var service = Executors.newFixedThreadPool(3);
        try {

            WithoutCyclicBarrier cleaner = new WithoutCyclicBarrier();
            for (int i = 0; i < 3; i++) {
                service.submit(() -> cleaner.clean());
            }
        } finally {
            service.shutdown();
        }
    }

    private void clean() {
        try {
            vacuumFloor();
            Thread.sleep(Math.round(Math.random() * 1000));
            coffeeBreak();
            Thread.sleep(Math.round(Math.random() * 1000));
            mopFloor();
            Thread.sleep(Math.round(Math.random() * 1000));
            turnOffLights();
            activateAlarm();
        } catch (InterruptedException exception ) {
            System.out.println(exception.getMessage());
        }
    }

    private void vacuumFloor() {
        System.out.println("Vacuming the floor...");
    }
    private void mopFloor() {
        System.out.println("Mopping the floor...");
    }

    private void coffeeBreak() {
        System.out.println("Time for a break!");
    }
    private void turnOffLights() {
        System.out.println("Turning off the lights...");
    }
    private void activateAlarm() {
        System.out.println("Activating the alarm...");
    }
}

Vacuming the floor...

Time for a break!

Mopping the floor...

Time for a break!

Mopping the floor...

Turning off the lights...

Activating the alarm...

Mopping the floor...

Turning off the lights...

Activating the alarm...

Turning off the lights...

Activating the alarm...