public CategoryExplorerTree() 
{
    super();
    CategoryNode rootNode = new CategoryNode("Categories");
    _model = new CategoryExplorerModel(rootNode);
    setModel(_model);
    init();
}

Construct a CategoryExplorerTree and create a default CategoryExplorerModel.

 public CategoryExplorerTree(CategoryExplorerModel model) 
{
  //--------------------------------------------------------------------------
  //   Private Variables:
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  //   Constructors:
  //--------------------------------------------------------------------------
    super(model);
    _model = model;
    init();
}

Construct a CategoryExplorerTree with a specific model.

 protected  void ensureRootExpansion() 
{
    _model.addTreeModelListener(new TreeModelAdapter() {
      public void treeNodesInserted(TreeModelEvent e) {
        expandRootNode();
      }
    });
}

 protected  void expandRootNode() 
{
    if (_rootAlreadyExpanded) {
      return;
    }
    _rootAlreadyExpanded = true;
    TreePath path = new TreePath(_model.getRootCategoryNode().getPath());
    expandPath(path);
}

 public CategoryExplorerModel getExplorerModel() 
{
    return (_model);
}

 public String getToolTipText(MouseEvent e) 
{
    try {
      return super.getToolTipText(e);
    } catch (Exception ex) {
      return "";
    }
}

 protected  void init() 
{
    // Put visible lines on the JTree.
    putClientProperty("JTree.lineStyle", "Angled");
    // Configure the Tree with the appropriate Renderers and Editors.
    CategoryNodeRenderer renderer = new CategoryNodeRenderer();
    setEditable(true);
    setCellRenderer(renderer);
    CategoryNodeEditor editor = new CategoryNodeEditor(_model);
    setCellEditor(new CategoryImmediateEditor(this,
        new CategoryNodeRenderer(),
        editor));
    setShowsRootHandles(true);
    setToolTipText("");
    ensureRootExpansion();
}