Выдает ошибку NullPointerException

На строчке message = textMessage.getText() выдает java.NullPointerException. В чем дело?

public class ParamFrame extends JDialog {
private final JPanel contentPanel = new JPanel();
private JTextField textAlarmHour;
private JTextField textAlarmMinute;
private JTextField textTimerHour;
private JTextField textTimerMinute;
private JTextPane textMessage;
private JRadioButton radioButtonAlarm;
private JRadioButton radioButtonTimer;
private int alarmHour;
private int alarmMinute;
private int timerHour;
private int timerMinute;
private String message;
private NotificationType notificationType;
public enum NotificationType {
    NONE,
    ALARM,
    TIMER;
}
/**
 * Launch the application.
 */

private int convertToInt (String value){
    if(value.isEmpty()) return 0;
    try {
        return Integer.parseInt(value);
    } catch (NumberFormatException e) {
    return 0;
    }
}
public ParamFrame (MainFrame owner){
    super(owner, "Параметры", true);
    setTitle("\u041D\u0430\u0441\u0442\u0440\u043E\u0439\u043A\u0430 \u043E\u043F\u043E\u0432\u0435\u0449\u0435\u043D\u0438\u044F");
    setAlwaysOnTop(true);
    setBounds(100, 100, 447, 377);
    getContentPane().setLayout(new BorderLayout());
    contentPanel.setBorder(new EmptyBorder(5, 5, 5, 5));
    getContentPane().add(contentPanel, BorderLayout.CENTER);
    contentPanel.setLayout(new BoxLayout(contentPanel, BoxLayout.Y_AXIS));
    {
        JPanel panelNotificationType = new JPanel();
        panelNotificationType.setAlignmentX(Component.LEFT_ALIGNMENT);
        panelNotificationType.setBorder(new TitledBorder(null, "\u041E\u043F\u043E\u0432\u0435\u0449\u0435\u043D\u0438\u0435", TitledBorder.LEADING, TitledBorder.TOP, null, null));
        contentPanel.add(panelNotificationType);
        panelNotificationType.setLayout(new BoxLayout(panelNotificationType, BoxLayout.Y_AXIS));
        {
            JRadioButton RadioButtonNone = new JRadioButton("\u041E\u0442\u0441\u0443\u0442\u0441\u0442\u0432\u0443\u0435\u0442");
            panelNotificationType.add(RadioButtonNone);
        }
        {
            Component horizontalGlue = Box.createHorizontalGlue();
            panelNotificationType.add(horizontalGlue);
        }
        {
            JRadioButton radioButtonAlarm = new JRadioButton("\u0411\u0443\u0434\u0438\u043B\u044C\u043D\u0438\u043A");
            panelNotificationType.add(radioButtonAlarm);
        }
        {
            JRadioButton radioButtonTimer = new JRadioButton("\u0422\u0430\u0439\u043C\u0435\u0440");
            panelNotificationType.add(radioButtonTimer);
        }
    }
    {
        JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.TOP);
        tabbedPane.setAlignmentX(Component.LEFT_ALIGNMENT);
        contentPanel.add(tabbedPane);
        {
            JPanel panelAlarm = new JPanel();
            tabbedPane.addTab("\u0411\u0443\u0434\u0438\u043B\u044C\u043D\u0438\u043A", null, panelAlarm, null);
            panelAlarm.setLayout(null);
            {
                JLabel label = new JLabel("\u0412\u0440\u0435\u043C\u044F \u0441\u0438\u0433\u043D\u0430\u043B\u0430 (\u0447:\u043C):");
                label.setHorizontalAlignment(SwingConstants.CENTER);
                label.setBounds(142, 11, 104, 14);
                panelAlarm.add(label);
            }
            textAlarmHour = new JTextField();
            textAlarmHour.setBounds(62, 36, 86, 20);
            panelAlarm.add(textAlarmHour);
            textAlarmHour.setColumns(10);
            textAlarmMinute = new JTextField();
            textAlarmMinute.setBounds(169, 36, 86, 20);
            panelAlarm.add(textAlarmMinute);
            textAlarmMinute.setColumns(10);
        }
        {
            JPanel panelTimer = new JPanel();
            tabbedPane.addTab("\u0422\u0430\u0439\u043C\u0435\u0440", null, panelTimer, null);
            panelTimer.setLayout(null);
            {
                JLabel label = new JLabel("\u0418\u043D\u0442\u0435\u0440\u0432\u0430\u043B \u0441\u0440\u0430\u0431\u0430\u0442\u044B\u0432\u0430\u043D\u0438\u044F \u0442\u0430\u0439\u043C\u0435\u0440\u0430 (\u0447:\u043C):");
                label.setBounds(63, 8, 201, 14);
                panelTimer.add(label);
            }
            textTimerHour = new JTextField();
            textTimerHour.setBounds(63, 33, 86, 20);
            panelTimer.add(textTimerHour);
            textTimerHour.setColumns(10);
            textTimerMinute = new JTextField();
            textTimerMinute.setBounds(178, 33, 86, 20);
            panelTimer.add(textTimerMinute);
            textTimerMinute.setColumns(10);
        }
    }
    {
        JScrollPane scrollPane = new JScrollPane();
        scrollPane.setAlignmentX(Component.LEFT_ALIGNMENT);
        contentPanel.add(scrollPane);
        {
            JTextPane textMessage = new JTextPane();
            scrollPane.setViewportView(textMessage);
        }
        {
            JLabel labelNotification = new JLabel("\u0421\u043E\u043E\u0431\u0449\u0435\u043D\u0438\u0435");
            scrollPane.setColumnHeaderView(labelNotification);
        }
    }
    {
        JPanel buttonPane = new JPanel();
        buttonPane.setLayout(new FlowLayout(FlowLayout.RIGHT));
        getContentPane().add(buttonPane, BorderLayout.SOUTH);
        {
            JButton okButton = new JButton("OK");
            okButton.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    notificationType = NotificationType.NONE;
                    message = textMessage.getText();
                    if(radioButtonAlarm.isSelected()) {
                        notificationType = NotificationType.ALARM;
                        alarmHour = convertToInt(textAlarmHour.getText());
                        alarmMinute = convertToInt(textAlarmMinute.getText());
                    }
                    if(radioButtonTimer.isSelected()) {
                        notificationType = NotificationType.TIMER;
                        timerHour = convertToInt(textTimerHour.getText());
                        timerMinute = convertToInt(textTimerMinute.getText());
                    }
                    setVisible(false);
                    dispose();
                }
            });
            okButton.setActionCommand("OK");
            buttonPane.add(okButton);
            getRootPane().setDefaultButton(okButton);
        }
        {
            JButton cancelButton = new JButton("\u041E\u0442\u043C\u0435\u043D\u0430");
            cancelButton.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    setVisible(false);
                    dispose();
                }
            });
            cancelButton.setActionCommand("Cancel");
            buttonPane.add(cancelButton);
        }
    }
}
public int getAlarmHour() {
    return alarmHour;
}
public int getAlarmMinute() {
    return alarmMinute;
}
public int getTimerHour() {
    return timerHour;
}
public int getTimerMinute() {
    return timerMinute;
}
public String getMessage() {
    return message;
}
public NotificationType getNotificationType() {
    return notificationType;
}

}