Stroke Patteren in Java Swing Example

import javax.swing.*; 
 import java.awt.*; 
 import java.awt.geom.*; 
 public class JStrokeJavaExample extends JFrame 
   { 
             public void paint(Graphics gr) 
             { 
                           super.paint(gr); 
                          Graphics2D GR2D = (Graphics2D)gr; 
                           BasicStroke strk = new BasicStroke(15.0f, 
                                 BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND); 
                           GR2D.setStroke(strk); 
                           GR2D.draw(new Rectangle2D.Double(50, 50, 100, 100)); 
             } 
                         public static void main(String[] ar) 
                          { 
                                JStrokeJavaExample frm = new JStrokeJavaExample(); 
                                frm.setSize(180, 200); 
                                frm.setVisible(true); 
                          } 
   }