I'm trying to update a JTree after it's already been created, so after
a few operations, I add more nodes to my root node and would like to
update it in my scrollpane. My problem is, when I add nodes to it, I
don't know how to make it visually update.

I have code like this that get's dynamically appended to throughout my
program.

---

DefaultMutableTreeNode books = new DefaultMutableTreeNode("books");

for (int i = 0; i < books.size(); i++) {
    books.add(new DefaultMutableTreeNode("Book: " + i));
}

root.add(books);
// now how to make the JTree visually update in the scrollpane

---

Any help much appreciated.