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

    public class Fenster{

    public Fenster(){
    startFrame();
    }

    public void startFrame(){

        /*Generate Frame*/
        JFrame frame = new JFrame("Tic Tac Toe");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        frame.setSize(500,500);

        /*Generate Headline and add to frame*/
        JLabel headline = new JLabel("Tic Tac Toe");
        frame.add(BorderLayout.NORTH, headline);

        /*Generate Panel for Buttons*/
        JPanel panel = new JPanel(new GridLayout(0,3));

        /*Generate Buttons*/
        JButton b1 = new JButton("");
        JButton b2 = new JButton("");
        JButton b3 = new JButton("");
        JButton b4 = new JButton("");
        JButton b5 = new JButton("");
        JButton b6 = new JButton("");
        JButton b7 = new JButton("");
        JButton b8 = new JButton("");
        JButton b9 = new JButton("");
        ActionListener al = new ActionListener() {
            public void actionPerformed( ActionEvent e ) {
            System.exit( 0 );
         }
        };
        b1.addActionListener(al);
        b1.setActionCommand("restart");

        /*Add Buttons to Panel*/
        panel.add(b1);
        panel.add(b2);
        panel.add(b3);
        panel.add(b4);
        panel.add(b5);
        panel.add(b6);
        panel.add(b7);
        panel.add(b8);
        panel.add(b9);

        /*Add Panel to Frame*/
        frame.add(BorderLayout.CENTER, panel);

    }

    public static void main(String[] args) {
        Fenster f= new Fenster();
    }


    }