how to set JTree line thickness?

[Matt Wilcko]

Anyone know how to set the thickness of lines that connect nodes in a JTree? By default, it is only one pixel. I need something a little thicker.

[Craig Wood]

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.plaf.ComponentUI;
import javax.swing.plaf.basic.BasicTreeUI;
import javax.swing.tree.*;
 
public class TreeTest
{
    public TreeTest()
    {
        JTree tree = getTree();
        tree.setUI(new CustomTreeUI());
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new JScrollPane(tree));
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    private JTree getTree()
    {
        String[] birds = {
            // branches |<-- child leaf nodes -->|
            "hawks", "gray", "red-tailed", "rough-legged",
            "falcons", "harrier", "kestrel", "kite", 
            "owls", "barred", "saw-whet", "snowy"
        };
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("birds");
        DefaultMutableTreeNode[] nodes = new DefaultMutableTreeNode[birds.length];
        for(int j = 0; j < nodes.length; j++)
            nodes[j] = new DefaultMutableTreeNode(birds[j]);
        for(int j = 0; j < 9; j += 4)
        {
            root.insert(nodes[j], j % 3);
            for(int k = j + 1; k < j + 4; k++)
                nodes[j].insert(nodes[k], k - j - 1);
        }
        DefaultTreeModel model = new DefaultTreeModel(root);
        return new JTree(model);
    }
 
    public static void main(String[] args)
    {
        new TreeTest();
    }
}
 
class CustomTreeUI extends BasicTreeUI
{
    public CustomTreeUI()
    {
        super();
    }
 
    public static ComponentUI createUI(JComponent x)
    {
        return new CustomTreeUI();
    }
 
    public void paint(Graphics g, JComponent c)
    {
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setStroke(new BasicStroke(3f));
        super.paint(g, c);
    }
}