public class Main {

    public static void main(String[] args) {
        int x = 1;
        String schrei = "David kanns jetzt";
        while(x <= 20) {
            System.out.println(schrei);
            x = x + 1;
        }
            if (x >= 20) playSound(url);
    }

    public static synchronized void playSound (final String url) {
        new Thread(new Runnable() {

            public void run() {
                try {
                    Clip clip = AudioSystem.getClip();
                    AudioInputStream inputStream = AudioSystem.getAudioInputStream(
                            Main.class.getResourceAsStream("C:\\Users\\David\\Desktop" + url));
                    clip.open(inputStream);
                    clip.start();
                } catch (Exception e) {
                    System.err.println(e.getMessage());
                }
            }
        }).start();
    }
}