public class App {

    public static void main(String[] args) {
        ExecutorService executor = Executors.newCachedThreadPool();

        executor.submit(new Runnable() {

            public void run() {
                Random random = new Random();
                int duration = random.nextInt(4000);

                System.out.println("Starting ... ");

                try {
                    Thread.sleep(duration);
                } catch (InterruptedException ex) {
                    Logger.getLogger(App.class.getName()).log(Level.SEVERE, null, ex);
                }

                System.out.println("Finished ... ");
            }
        });
        executor.shutdown();
    }
}