Demo.java

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

public class Demo {

    public static void main(String[] args) {
//        JLabel northLabel = new JLabel("North");


        JFrame application = new JFrame();

        application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

//        // add the labels to the frame; the second argument specifies
//        // where on the frame to add the label
//        application.add(northLabel, BorderLayout.NORTH);
//
//        application.add(new Panel(), BorderLayout.CENTER);
//


        JLabel label = new JLabel("Sevval");
        JLabel labelYigit = new JLabel("Yigit");


        application.add(label, BorderLayout.NORTH);
        application.add(labelYigit, BorderLayout.CENTER);
        application.add(new KendiPanelim(), BorderLayout.CENTER);



        application.setSize(500, 500); // set the size of the frame
        application.setVisible(true);

    }

    static class KendiPanelim extends JPanel {


        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.setColor(Color.GREEN);

            g.fillArc(10, 10, 100, 100, 0, 90);
        }

    }
}