Java JTree remove tree node by user object

import java.awt.Container;
import java.awt.FlowLayout;
import java.util.ArrayList;
import java.util.Iterator;

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.TreeModel;

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  w  w  w .  j av a 2s .  c o m*/
      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);

      removeNode("demo2s.com", t); 

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

   /**
    * Remove a TreeNode containing the specified obj from a JTree. It is assumed
    * that all TreeNodes in the specified tree are DefaultMutableTreeNodes and its
    * TreeModel should be a DefaultTreeModel.
    * 
    * @param obj  the contained
    * @param tree the JTree whose TreeNodes are DefaultMutableTreeNodes.
    */
   public static void removeNode(Object obj, JTree tree) {
      DefaultMutableTreeNode treeNode = searchNode(obj, tree);
      DefaultTreeModel model = (DefaultTreeModel) tree.getModel();
      model.removeNodeFromParent(treeNode);
   }

   /**
    * Search a DefaultMutableTreeNode whose userObject is the specified obj.
    * 
    * @param obj  the userObject.
    * @param tree the JTree whose TreeNodes are DefaultMutableTreeNodes.
    * @return a DefaultMuatbleTreeNode whose userObject is obj.
    */
   public static DefaultMutableTreeNode searchNode(Object obj, JTree tree) {
      TreeModel model = tree.getModel();
      DefaultMutableTreeNode root = (DefaultMutableTreeNode) model.getRoot();
      if (root.getUserObject() == obj)
         return root;
      return searchNode(obj, root);
   }

   /**
    * A recursive method to search a DefaultMutableTreeNode that displays an Object
    * obj.
    */
   public static DefaultMutableTreeNode searchNode(Object obj, DefaultMutableTreeNode parentNode) {
      DefaultMutableTreeNode treeNode = null;
      int size = parentNode.getChildCount();
      // A list of nodes with children
      java.util.List parentNodes = new ArrayList();
      for (int i = 0; i < size; i++) {
         treeNode = (DefaultMutableTreeNode) parentNode.getChildAt(i);
         if (treeNode.getUserObject() == obj)
            return treeNode;
         if (treeNode.getChildCount() > 0)
            parentNodes.add(treeNode);
      }
      for (Iterator it = parentNodes.iterator(); it.hasNext();) {
         treeNode = searchNode(obj, (DefaultMutableTreeNode) it.next());
         if (treeNode != null)
            return treeNode;
      }
      return null;
   }
}