GroupLayout можно использовать только с одним контейнером одновременно

не уверен, почему эта ошибка возникает. Я использую GroupLayout, потому что хочу, чтобы он делал интервал для меня и будет добавлять больше панелей в кадр в будущем. Ниже приведена трассировка стека.

Exception in thread "main" java.lang.IllegalArgumentException: GroupLayout can only be used with one Container at a time
    at javax.swing.GroupLayout.checkParent(Unknown Source)
    at javax.swing.GroupLayout.invalidateLayout(Unknown Source)
    at java.awt.Container.invalidate(Unknown Source)
    at java.awt.Component.addNotify(Unknown Source)
    at java.awt.Container.addNotify(Unknown Source)
    at javax.swing.JComponent.addNotify(Unknown Source)
    at java.awt.Container.addNotify(Unknown Source)
    at javax.swing.JComponent.addNotify(Unknown Source)
    at java.awt.Container.addNotify(Unknown Source)
    at javax.swing.JComponent.addNotify(Unknown Source)
    at javax.swing.JRootPane.addNotify(Unknown Source)
    at java.awt.Container.addNotify(Unknown Source)
    at java.awt.Window.addNotify(Unknown Source)
    at java.awt.Frame.addNotify(Unknown Source)
    at java.awt.Window.pack(Unknown Source)
    at client.AlternateGUI.drawGui(AlternateGUI.java:54)
    at client.AlternateGUI.main(AlternateGUI.java:24)

вот код:

package client;

import java.awt.Component;*

public class AlternateGUI {
    private JList people;
    private DefaultListModel dlm;
    private JLabel l1, l2, l3;
    private JFrame alternateGUIFrame;
    private final static ImageIcon unavailableIcon = new ImageIcon("offline.png");

    public static void main(String[] args)
    {
        AlternateGUI ls = new AlternateGUI();
        ls.drawGui();
    }

    public AlternateGUI(){
        dlm = new DefaultListModel();
        people = new JList(dlm);

        alternateGUIFrame = new JFrame();

        JScrollPane peopleScroller = new JScrollPane(people, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
        people.setCellRenderer(new CellRenderer());

        GroupLayout alternateGUILayout = new GroupLayout(alternateGUIFrame);
        alternateGUIFrame.setLayout(alternateGUILayout);

        alternateGUILayout.setAutoCreateGaps(true);
        alternateGUILayout.setAutoCreateContainerGaps(true);
        alternateGUILayout.setHorizontalGroup(alternateGUILayout.createSequentialGroup()
                .addComponent(peopleScroller));
        alternateGUILayout.setVerticalGroup(alternateGUILayout.createSequentialGroup()
                .addComponent(peopleScroller));
        }

    public void drawGui() {
        l1 = new JLabel("Hi", unavailableIcon , JLabel.LEFT);
        l2 = new JLabel("Hello", unavailableIcon , JLabel.LEFT);
        l3 = new JLabel("Bye", unavailableIcon , JLabel.LEFT);
        dlm.addElement(l1);
        dlm.addElement(l2);
        dlm.addElement(l3);

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

    class CellRenderer implements ListCellRenderer
    {
        public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus)
        {
            Component com = (Component)value;
            return com;
        }
    }
}