Rather Specific JList Conundrum

Question

Hi Guys,
I've come to a bit of a brick wall on the project I'm working on, but as my problem is so specific no amount of Googling is helping me.
Essentially my coursework is to make a twitter client using the Twitter4JAPI, the part I'm stuggling with is showing the home feed. I want it to show the Icon, with the User and Status next to it which I'm doing using my own custom cell renderer. Now it works fine, but the program takes ages to load as it pulls all the avatars off the web, swapping to and from that tab takes ages (for the same reason), and scrolling the list is so mind blowingly slow, as every tick it refreshes all the images (from the web).
Any suggestions how to stop this?
Here is my custom cell renderer code:
public Component getListCellRendererComponent(JList list, Object value,
               int index, boolean isSelected, boolean cellHasFocus) {
          input = value.toString();
          final String splitArray[] = input.split("`");
          Image avatar = null;
          try {
               final URL avatarURL = new URL(splitArray[0]);
               avatar = ImageIO.read(avatarURL);
          } catch (final IOException e) {
               JOptionPane.showMessageDialog(null,
                         "Error retriving some users avatars",
                         "Image download error", JOptionPane.ERROR_MESSAGE);
          usersAvatar.setIcon(new ImageIcon(avatar));
          tweet.setText(splitArray[2]);
          userName.setText(" " + splitArray[1] + "    ");
          return mainPanel;
     }I cut out all the layout junk.
And the input for the list is in the form avatarurl`username`tweet, which is then split and stored in the split array.
I've had a bash at threading it based on [Improve Application Performance With SwingWorker in Java SE 6|http://java.sun.com/developer/technicalArticles/javase/swingworker/] but it meant that the avatars were all identical.
Do I need to thread the entire list creation section instead of just the image retrival.
All help greatly appreciated.
For your reference --->

Answer 1

I can safely say you answered my question.
The 2 classes I added were:
User Class import javax.swing.ImageIcon;
public class UserClass {
     String userName;
     ImageIcon userAvatar;
     public UserClass(String user, ImageIcon avatar) {
          userName = user;
          userAvatar = avatar;
     public String getUserName() {
          return userName;
     public ImageIcon getUserAvatar() {
          return userAvatar;
}and UserDB
import java.awt.Image;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
public class UserDB {
     private ArrayList<UserClass> users;
     public UserDB(){
          users = new ArrayList<UserClass>();
     public ImageIcon getAvatar(String username){
          ImageIcon avatar = null;
          for (int i = 0; i < users.size(); i++) {
               String beingChecked = users.get(i).getUserName();
               if (username.equals(beingChecked)) {
                    avatar = users.get(i).getUserAvatar();
          return avatar;
     public String getUserName(int index){
          return users.get(index).getUserName();
     public int getTotalUsers() {
          return users.size();
     public void addUser(String userName, URL profileImageURL){
          Image avatar = null;
          try {
               final URL avatarURL = profileImageURL;
               avatar = ImageIO.read(avatarURL);
          } catch (final IOException e) {
          ImageIcon avatarIcon = new ImageIcon(avatar);
          UserClass tooAdd = new UserClass(userName, avatarIcon);
          users.add(tooAdd);
     public boolean isEmpty(){
          return users.isEmpty();
}So now the first time it encounters a unique user for the first time it add's it too the database.
Honestly that's an approach i would never have thought of in a million years!
Thanks a bunch