public class Frame extends JFrame
{
    JButton copy;
    JPanel p;

    public Frame()
    {
        super("");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(500, 500);

        p = new JPanel();

        copy = new JButton("Copy");
        copy.addActionListener(new ActionListener()
        {

            @Override
            public void actionPerformed(ActionEvent arg0)
            {
                p.add(new JButton("Added"));

                revalidate();
            }
        });

        p.add(copy);

        add(p);
        setVisible(true);
    }

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