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

public class Flow {
    public static void main(String[] args) {
        JFrame vindu = new JFrame("Flow");
        JPanel panel = new JPanel();
        vindu.add(panel);
        vindu.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        vindu.setPreferredSize(new Dimension(300, 100));

        JButton knapp1 = new JButton("Knapp1");
        JButton knapp2 = new JButton("Knapp2");
        JButton knapp3 = new JButton("Knapp3");
        JButton knapp4 = new JButton("Knapp4");

        panel.add(knapp1);
        panel.add(knapp2);
        panel.add(knapp3);
        panel.add(knapp4);

        vindu.pack();
        vindu.setLocationRelativeTo(null);
        vindu.setVisible(true);
    }
}