I would suggest a timer. Here is an example I have written for you. This is
a J# WinForms app that will run for 5 seconds and then shutdown.

I'm using a timer (private System.Threading.Timer) to start a method
(private void TimerShutdown( Object arg )) after 5 seconds. As you can see
in the example, I'm creating the timer instance in the constructor.

import System.Drawing.*;
import System.Collections.*;
import System.ComponentModel.*;
import System.Windows.Forms.*;
import System.Data.*;

/**
* Summary description for Form1.
*/
public class Form1 extends System.Windows.Forms.Form
{
private System.ComponentModel.Container components = null;

// Timer
private System.Threading.Timer timer = null;

public Form1()
{
 InitializeComponent();

 // Maka the Timer
 this.timer = new System.Threading.Timer(
  new System.Threading.TimerCallback(TimerShutdown), // Method to be called
  null,
  5000, // 5 sec
  0 );
}

// The timer method
private void TimerShutdown( Object arg )
{
 System.exit(0);
}

protected void Dispose(boolean disposing)
{
 if (disposing)
 {
  if (components != null)
  {
   components.Dispose();
  }
 }
 super.Dispose(disposing);
}

private void InitializeComponent()
{
 this.SuspendLayout();
 this.set_AutoScaleBaseSize(new System.Drawing.Size(5, 13));
 this.set_ClientSize(new System.Drawing.Size(292, 266));
 this.set_Name("Form1");
 this.set_Text("Form1");
 this.ResumeLayout(false);

}

/** @attribute System.STAThread() */
public static void main(String[] args)
{
 Application.Run(new Form1());
}
}

Regards,
Lars-Inge T?nnessen