File Exporting problems, in Eclipse.

Hello, i have programmed a game using JPanel and JFrame. My App is of this type:


public class Main extends JPanel {

private JFrame frame;


     public static void main(String[] args) {
             new Main();
   }  
     public Main() {
        frame.setSize(WIDTH, HEIGHT);
        //and rest of the normal methods for frame and all the initialization...
       Thread thread = new Thread();
        thread.start();
     }
     public void run() {
        repaint();
        update();
      }
}

The problem is, When i export the file in eclipse as Runnable jar file, and run the exported file, it gives me a blank screen (white default) and nothing is running. Whereas, normal debugging of the game is working quite well. Could anyone help me with this?
Thank you.