Swing/AWT/SWT :: Build Code To Call Class As JTree?

I am trying to make a JTree. I have used this guide :[URL]

Now when I call my Class with

TreeMainMenu tree = new TreeMainMenu();
JScrollPane MainMenu = new JScrollPane(tree);

I get only the default JTree..

I need to understand how I should build my code to call the class as JTree.

This is my code:

public class TreeMainMenu extends JTree {
private DefaultMutableTreeNode top = new DefaultMutableTreeNode("TOP");
JTree tree;
public JTree TreeMainMenu() {
APNode();
tree = new JTree(top);
tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
return tree;

[code]....