JTreeのノード間の接続線の色を変更する

UIManager.put("Tree.paintLines", Boolean.TRUE);
UIManager.put("Tree.lineTypeDashed", Boolean.TRUE);
UIManager.put("Tree.line", Color.GREEN);
UIManager.put("Tree.hash", Color.RED);

JTree tree0 = new JTree();

JTree tree1 = new JTree();
tree1.putClientProperty("JTree.lineStyle", "Horizontal");

JTree tree2 = new JTree();
tree2.setUI(new BasicTreeUI() {
  private final Stroke horizontalLine = new BasicStroke(2f);
  private final Stroke verticalLine = new BasicStroke(5f);

  @Override public Color getHashColor() {
    return Color.BLUE;
  }

  @Override protected void paintHorizontalPartOfLeg(
      Graphics g, Rectangle clipBounds, Insets insets,
      Rectangle bounds, TreePath path, int row,
      boolean isExpanded, boolean hasBeenExpanded, boolean isLeaf) {
    Graphics2D g2 = (Graphics2D) g.create();
    g2.setStroke(horizontalLine);
    super.paintHorizontalPartOfLeg(
        g2, clipBounds, insets, bounds, path, row,
        isExpanded, hasBeenExpanded, isLeaf);
    g2.dispose();
  }

  @Override protected void paintVerticalPartOfLeg(
      Graphics g, Rectangle clipBounds, Insets insets, TreePath path) {
    Graphics2D g2 = (Graphics2D) g.create();
    g2.setStroke(verticalLine);
    super.paintVerticalPartOfLeg(g2, clipBounds, insets, path);
    g2.dispose();
  }
});