Java SE (Java Platform, Standard Edition)

Hi,

I used the following code from an example:

see link
http://java.sun.com/docs/books/tutorial/uiswing/components/tree.html

//...where the tree is initialized:
    //Enable tool tips.
    ToolTipManager.sharedInstance().registerComponent(tree);
    
    ImageIcon tutorialIcon = createImageIcon("images/middle.gif");
    if (tutorialIcon != null) {
        tree.setCellRenderer(new MyRenderer(tutorialIcon));
    }
...
class MyRenderer extends DefaultTreeCellRenderer {
    Icon tutorialIcon;

    public MyRenderer(Icon icon) {
        tutorialIcon = icon;
    }

    public Component getTreeCellRendererComponent(
                        JTree tree,
                        Object value,
                        boolean sel,
                        boolean expanded,
                        boolean leaf,
                        int row,
                        boolean hasFocus) {

        super.getTreeCellRendererComponent(
                        tree, value, sel,
                        expanded, leaf, row,
                        hasFocus);
        if (leaf && isTutorialBook(value)) {
            setIcon(tutorialIcon);
            setToolTipText("This book is in the Tutorial series.");
        } else {
            setToolTipText(null); //no tool tip
        } 

        return this;
    }

    protected boolean isTutorialBook(Object value) {
        DefaultMutableTreeNode node =
                (DefaultMutableTreeNode)value;
        BookInfo nodeInfo =
                (BookInfo)(node.getUserObject());
        String title = nodeInfo.bookName;
        if (title.indexOf("Tutorial") >= 0) {
            return true;
        }

        return false;
    }
}

I use above code to customize the Icon of JTree at run time.
When I Drag and drop the node/leaf into this Jtree, I can successfully see the JTee's icon was changed with new coming Icon, but problem is that the whole tree's Leave's icon were replaced by new COMING new leaf/node's icon, what I want is that I hope to keep all previous leaves/nodes' icons untouched or unchanged, not replaced by new coming icon, how to implement this??

Can any guru give some valuable advice??

Really thanks.