Create a 1000 millisecond timer that gets the current date and time then format them and write them out to the status bar.

Sample code:

timer = new Timer( ONE_SECOND, new ActionListener()
{
   public void actionPerformed( ActionEvent evt )
   {
     Date date = new Date();
     if ( date != oldDate )
     {
        // Only update when date changes
        String strDate = DateFormat.getDateInstance().format( date );
        *** code to write strDate to status bar ***
        oldDate = date;
     }

     String strTime = DateFormat.getTimeInstance().format( date );
     *** code to write strTime to status bar ***
  }
} );

// Start the timer
timer.start();

// Add a finalize method to stop the timer when the app is terminated
protected void finalize()
{
  timer.stop();
}