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

public class Demo1{

    public static void main(String[] args) {
        JFrame vindu = new JFrame();
        vindu.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JPanel basis = new JPanel();

        JButton printKnapp = new JButton("Legesystem");
        class KlikketPaa implements ActionListener{
            @Override
            public void actionPerformed(ActionEvent event){
                System.out.println("?sj");
            }
        }
        printKnapp.addActionListener(new KlikketPaa());
        
        basis.add(printKnapp);

        vindu.add(basis);


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