JList(Vector) inside JScrollPane vanishes!

Question

Hi all, I have a problem thats driving me crazy, Im really stumped on this one;
Im trying to update the GUI on a packet sniffer I wrote a while ago,
I have a GUI class below as part of a larger program, this class containes a JList(Vector) inside a JScrollPane inside a JPanel inside a JFrame, I want this JList to be on the screen all the time, and grow dynamically as new elements are added to the Vector.
Elements are added via an accessor method addPacket(Capture), you can assume the other classes in my program work fine.
The problem is, the JFrame periodically goes blank, sometimes the scrollbars are present, sometimes not. After a while (sometimes) the JList reappears, containing the list of packets as it should, but it never lasts very long. Often it will disappear permanently.
The class below is pretty short and simple, I really hope this is a simple and obvious mistake Ive made that someone can spot.
Thanks,
Soothsayer
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.io.InputStream;
public class GUI extends JFrame
     Dimension screenResolution = Toolkit.getDefaultToolkit().getScreenSize();
     private InputStream fontStream = this.getClass().getResourceAsStream("console.ttf");
     Font outputFont;
     static final Color FIELD_COLOR = new Color(20, 20, 60);
     static final Color FONT_COLOR = new Color(150, 190, 255);
     private static JPanel superPanel = new JPanel();
     private static Vector<Capture> packetList = new Vector<Capture>(1000, 500);
     private static JList listObject = new JList(packetList);
     private static JScrollPane scrollPane = new JScrollPane(listObject);
     public GUI()
          super("LineLight v2.1 - Edd Burgess");
          this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          this.setLocation(50, 10);
          try { outputFont = Font.createFont(Font.TRUETYPE_FONT, fontStream); }
          catch(Exception e) { System.err.println("Error Loading Font:\n" + e); }
          outputFont = outputFont.deriveFont((float)10);
          listObject.setFont(outputFont);
          superPanel.setPreferredSize(new Dimension(screenResolution.width - 100, screenResolution.height - 100));
          superPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 0, 0));
          scrollPane.setPreferredSize(new Dimension(screenResolution.width - 100, screenResolution.height - 100));
          scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
          scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
          scrollPane.setWheelScrollingEnabled(true);
          superPanel.add(scrollPane);
          this.add(superPanel);
          this.pack();
     public void addPacket(Capture c)
          this.packetList.add(c);
          this.listObject.setListData(packetList);
          this.superPanel.repaint();
}

Answer 1

I'm having basically the same problem, And how is your code different than the example in the tutorial???
You can also read the tutorial section on "Concurrency".
If you need further help then you need to create a [Short, Self Contained, Compilable and Executable, Example Program (SSCCE)|http://homepage1.nifty.com/algafield/sscce.html], that demonstrates the incorrect behaviour.
Don't forget to use the Code Formatting Tags so the posted code retains its original formatting. That is done by selecting the code and then clicking on the "Code" button above the question input area.
Start your own posting if you need further help.