import java.awt.*;
import javax.swing.*;
public class OKNA {

	public static void main(String[] args) {
		myFrame okno = new myFrame();
	}
}
	class myFrame extends JFrame
	{
		public myFrame()
		{
		myPanel panel = new myPanel();
        Container cont = getContentPane();
        cont.add(panel);
        setBounds(10, 10, 300, 400);
        setVisible(true);
	}

	}

class myPanel extends JPanel
{
	public void paintComponent(Graphics gr)
	{
	super.paintComponent(gr);
	gr.setColor(Color.BLUE);
	gr.fillRect(10,10,200,300);
	}
}