Updating Time In Java

My program is working fine. When I executes it, it shows me this:

The clock is 54 minutes over 23 (+41 seconds.

and when i press ENTER, it shows me this:

23:54:41

But then it won't show me the update. I want to update the time, for example when I started the execution the time was 23:54:41 but it must show me something like 23:54:45, because I need the current time.

I have searched the whole internet about this but I don't know how to use the "Date.update ();".

Here is my code

package p2;

import java.util.Calendar;
import java.util.Date;
import javax.swing.JOptionPane;
public class Time {
public void myTime() {
Calendar cal = Calendar.getInstance();

[Code] ....