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

class Program extends JFrame
{
	JList listabox;
	DefaultListModel listaModel;
	JButton gomb;
        Program()
        {
                setLayout(null);		
                
		listaModel = new DefaultListModel();		
		listaModel.addElement("Első");
		listaModel.addElement("Második");

		listabox = new JList(listaModel);		
		
		JScrollPane listaPane = new JScrollPane(listabox);
		listaPane.setBounds(100, 100, 100, 100);
		
		gomb = new JButton("Hozzáad");
                gomb.addActionListener(new ActionListener() {
                	public void actionPerformed(ActionEvent e) {
				listaModel.addElement("Harmadik");				
                        }
                });
		gomb.setBounds(20, 20, 100, 30);		
		
		add(listaPane);
		add(gomb);
                
		setSize(800,600);
		setVisible(true);
        } 
        public static void main(String args[])
        {
                new Program();
        }
}