date spinner error MCVE

import java.util.Calendar;
import java.util.Date;

import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

@SuppressWarnings("serial")
public class DateSpinner2 extends JPanel {
   private Date date = new Date();
   private JSpinner dateSpinner = new JSpinner(new SpinnerDateModel(date, null,
         null, Calendar.WEEK_OF_YEAR));

   public DateSpinner2() {
      String dateFormatPattern = "w";
      JSpinner.DateEditor editor = new JSpinner.DateEditor(dateSpinner, dateFormatPattern);
      dateSpinner.setEditor(editor);
      add(dateSpinner);

      dateSpinner.addChangeListener(new ChangeListener() {

         @Override
         public void stateChanged(ChangeEvent e) {
            System.out.println(dateSpinner.getValue());
         }
      });
   }

   private static void createAndShowGui() {
      DateSpinner2 mainPanel = new DateSpinner2();

      JFrame frame = new JFrame("DateSpinner2");
      frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}