Developing Java Explorer

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im trying to build a Java Explorer(a la Windows Explorer). Ths following code goes to some extent. im getting 2 problems :

=> The Folders and Files are not in alphabetic order. how do i get it ??(folders first and then files)
=> im able to expand the tree to only one branch. how can i expand it to 'n' branches ??

plzz somebody help me. :(

killi

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import java.io.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.tree.*;
import javax.swing.event.*;

public class JavaExplorer extends JFrame implements MouseListener
 {
   JPanel pnlTop, pnlMain;
   JTextPane txtpane;
   JButton btn;
   JSplitPane split;
   JScrollPane jspTree, jspDisp;
   JTree tree;
   DefaultMutableTreeNode root, branch, branch1;

   File folder = new File("d:/Killi/Java/Swings");

   Container c;

   public JavaExplorer()
    {
      c = getContentPane();
      c.add(pnlTop  = new JPanel(), "North");
      c.add(pnlMain = new JPanel());
      pnlMain.setLayout(new BorderLayout());
      pnlTop.add(btn = new JButton("Click"));

      root = new DefaultMutableTreeNode(folder.getPath());
      createNodes(root);
      JTree tree = new JTree(root);
      tree.putClientProperty("JTree.lineStyle", "Angled");
      pnlMain.add(split = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, jspTree = new JScrollPane(tree), jspDisp = new JScrollPane(txtpane = new JTextPane())));
      split.setDividerLocation(225);

      setSize(500,300);
      setLocation(100,100);
      setVisible(true);
      setTitle("Java Explorer");

      tree.addMouseListener(this);
      addWindowListener(new WindowAdapter()
       {
          public void windowClosing(WindowEvent we)
           { System.exit(0); }
       });
    }

   public void createNodes(DefaultMutableTreeNode root)
    {
      File[] list = folder.listFiles();

      for(int i=0; i<list.length; i++)
       {
         if(list[i].isFile())
          {
            branch = new DefaultMutableTreeNode(list[i]);
            root.add(branch);
          }

         if(list[i].isDirectory())
          {
            branch = new DefaultMutableTreeNode(list[i]);
            root.add(branch);

            File[] list1 = list[i].listFiles();

            for(int j=0; j<list1.length; j++)
             {
               branch1 = new DefaultMutableTreeNode(list1[j]);
               branch.add(branch1);
             }
          }
       }
    }

   public void mouseEntered(MouseEvent me) {}
   public void mouseExited(MouseEvent me) {}
   public void mousePressed(MouseEvent me) {}
   public void mouseReleased(MouseEvent me) {}
   public void mouseClicked(MouseEvent me)
    {
      JOptionPane.showMessageDialog(null, branch1, "Mouse Cick", JOptionPane.INFORMATION_MESSAGE); // this is just for debugging purpose
    }

   public static void main(String args[])
    { new JavaExplorer(); }
 }

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