Java JTree expand tree node by DefaultMutableTreeNode

import java.awt.Container;
import java.awt.FlowLayout;
import java.util.Enumeration;
import java.util.Set;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;

public class Main {
   public static void main(String args[]) {
      final JFrame f = new JFrame("JTree Demo");
      f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      Container c = f.getContentPane();
      c.setLayout(new FlowLayout());
      DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
      DefaultMutableTreeNode c1 = new DefaultMutableTreeNode("X");
      DefaultMutableTreeNode c2 = new DefaultMutableTreeNode("B");
      DefaultMutableTreeNode c3 = new DefaultMutableTreeNode("C");
      root.add(c1);/*from   ww w.java 2  s.com*/
      root.add(c2);
      root.add(c3);

      c1.add(new DefaultMutableTreeNode("1"));
      c1.add(new DefaultMutableTreeNode("2"));

      c2.add(new DefaultMutableTreeNode("3"));
      c2.add(new DefaultMutableTreeNode("4"));

      c3.add(new DefaultMutableTreeNode("5"));
      DefaultMutableTreeNode n6 = new DefaultMutableTreeNode("6");
      n6.setUserObject("demo2s.com");
      c3.add(n6);

      JTree t = new JTree(root);

      expandAllNodes(root,t);

      c.add(new JScrollPane(t));
      f.pack();
      f.setVisible(true);
   }

   /**
    * Expand all tree nodes under the specified DefaultMutableTreeNode object.
    * @param treeNode
    * @param tree a JTree with DefaultTreeModel as its model.
    */
   public static void expandAllNodes(DefaultMutableTreeNode treeNode,
           JTree tree) {
       DefaultTreeModel model = (DefaultTreeModel) tree.getModel();
       Enumeration enum1 = treeNode.breadthFirstEnumeration();
       while (enum1.hasMoreElements()) {
           treeNode = (DefaultMutableTreeNode) enum1.nextElement();
           if (treeNode.getChildCount() > 0) {
               TreePath path = new TreePath(model.getPathToRoot(treeNode));
               tree.expandPath(path);
           }
       }
   }
}