Java create background thread which does something periodically

Is it possible to create a separate background thread which would separately do some stuff? I've tried the following program but it doesn't work as I expect.

public class Test {

    private static class UpdaterThread extends Thread {
        private final int TIMEOUT = 3000;

        public void run() {
            while (true) {
                try {
                    Thread.sleep(TIMEOUT);
                    System.out.println("3 seconds passed");
                } catch (InterruptedException ex) {
                }
            }
        }
    }

    /**
     * @param args
     *            the command line arguments
     */
    public static void main(String[] args) {
        try {
            Thread u = new UpdaterThread();
            u.start();
            while (true) {
                System.out.println("--");
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

I expected that every 3 seconds "3 seconds passed" will be printed in the flow of multiple "--" strings. In fact "3 seconds passed" is never printed. Why? And how can I create a background thread which would do something independantly from the main thread?