How to improve this timer code ??

Question

Dear Sir:
I have following code, it can works and if I remove the line "new JFrame("New Test Timer").setVisible(true);"
Then It did not show up timer message,
What is wrong here??
I want to remove this line but still keep timer moving,
How to do this??
Thanks
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.Timer;
public class TimerSample {
  public static void main(String args[]) {
    new JFrame("New Test Timer").setVisible(true);
    ActionListener actionListener = new ActionListener() {
      public void actionPerformed(ActionEvent actionEvent) {
        System.out.println("Hello World Timer");
    Timer timer = new Timer(1000, actionListener);
    timer.start();
}

Answer 1

Swing timers are called in the event dispatch thread. If you don't start the event dispatch thread (by setting your GUI visible) then they don't get called.
If you want a timer but you don't want a GUI, then use a java.util.Timer.