his is my code, I need a JTextArea on JTree nodes. someone can help me?

import javax.swing.*;
import javax.swing.tree.*;
import java.awt.*;
import java.awt.event.*;
import java.util.EventObject;
import javax.swing.event.*;

public class Trees extends JFrame
{
JTree a;
DefaultMutableTreeNode node1;
DefaultMutableTreeNode node2;
DefaultMutableTreeNode node3;
JPanel p;

public Trees()
{
p=new JPanel();
node1 = new DefaultMutableTreeNode("node1");
node2 = new DefaultMutableTreeNode("node2");
a=new JTree(node1);
JTextAreaNodeRenderer j=new JTextAreaNodeRenderer();
a.setCellRenderer(j);
j.getTreeCellRendererComponent(a, null, true, true, true, 1, true);
node1.add(node2);
p.add(a);
a.setEditable(true);
setContentPane(p);
setVisible(true);
}

class JTextAreaNodeRenderer implements TreeCellRenderer
{
JTextArea ta;
public JTextArea getTreeCellRendererComponent(JTree tree, Object value,
boolean selected, boolean expanded, boolean leaf, int row, boolean
hasFocus)
{
ta = new JTextArea(5,20);
ta.setEditable(true);
return ta;
}
}

public static void main(String[]args)
{
Trees al = new Trees();
}
}