import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class randCircle extends JPanel {
    private JFrame f;
    private JPanel p;

    public randCircle() {
        f = new JFrame("Bullseye");
        p = new JPanel();

        f.setBackground(Color.cyan);
        p.setPreferredSize(new Dimension(400, 400));
    }

    public void paint(Graphics g) {
        super.paint(g);
        g.setColor(Color.gray);
        g.fillOval(0, 0, 20, 20);
    }

    public void display() {
        f.add(p);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setVisible(true);
        f.pack();
    }
}

// Main Class

public class randCircleMain {
    public static void main(String args[]) {
        randCircle panel = new randCircle();
        panel.display();
    }
}