package  test.swing;

 import  javax.swing.*;
 import  java.awt.*;
 import  java.awt.geom.Rectangle2D;

 public   class  DrawSquare  extends  JFrame {
   public  DrawSquare(String title)  throws  HeadlessException {
     super (title);

    DPanel dPanel =  new  DPanel();
    getContentPane().add(dPanel);

    setDefaultCloseOperation(EXIT_ON_CLOSE);
    pack();
  }

   public   static   void  main(String[] args) {
    DrawSquare ds =  new  DrawSquare("Test");
    ds.setVisible(true);
  }

   class  DPanel  extends  JPanel {
     protected   void  paintComponent(Graphics g) {
       super .paintComponent(g);

      Graphics2D g2d = (Graphics2D) g;
      g2d.setColor(Color.blue);
      g2d.setStroke( new  BasicStroke( 6 ));
      Rectangle2D rect =  new  Rectangle2D. Double ( 10 ,  10 ,  90 ,  90 );
      g2d.draw(rect);
    }

     public  Dimension getPreferredSize() {
       return   new  Dimension( 110 ,  110 );
    }
  }
}