Change the Thickness of the Stroke in Java

import java.awt.BasicStroke;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
//from  w  ww  . jav a  2 s  .  c  o  m
import javax.swing.JComponent;
import javax.swing.JFrame;

class MyCanvas extends JComponent {
  public void paint(Graphics g) {
    Graphics2D g2d = (Graphics2D) g;
    float strokeThickness = 5.0f;

    BasicStroke stroke = new BasicStroke(strokeThickness);
    g2d.setStroke(stroke);

    g2d.draw(new Rectangle(20,20,200,200));
  }
}

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);
  }
}