Draw a line with Line2D.Double in Java

/* w ww . j ava  2  s.com*/
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Line2D;

import javax.swing.JComponent;
import javax.swing.JFrame;

class MyCanvas extends JComponent {
  public void paint(Graphics g) {
    Graphics2D g2 = (Graphics2D) g;

    // draw a rectangle

    double leftX = 100;
    double topY = 100;
    double width = 200;
    double height = 150;

    g2.draw(new Line2D.Double(leftX, topY, leftX + width, topY + height));

  }
}

public class Main {
  public static void main(String[] a) {
    JFrame window = new JFrame();
    window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    window.setBounds(30, 30, 450, 450);
    window.getContentPane().add(new MyCanvas());
    window.setVisible(true);
  }
}