Union two Rectangles in Java

    /*from  w ww.  java 2 s . c o  m*/
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;

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

class MyCanvas extends JComponent {
  public void paint(Graphics g) {
    Rectangle r = new Rectangle(50, 50, 100, 100);
    Rectangle r1 = new Rectangle(100, 100, 75, 75);
    g.setColor(Color.lightGray);
    Rectangle r2 = r.union(r1);
    g.fillRect(r2.x, r2.y, r2.width, r2.height);
    g.setColor(Color.black);
    g.drawRect(r.x, r.y, r.width, r.height);
    g.drawRect(r1.x, r1.y, r1.width, r1.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);
  }
}