Java SwingWorker get return value from time consuming task

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.List;
import java.util.Random;
import java.util.concurrent.ExecutionException;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingWorker;

class MyPanel extends JPanel {

  public MyPanel() {
    setLayout(new BorderLayout());

    // build buttons start and cancel
    JPanel buttonsArea = new JPanel(new FlowLayout(FlowLayout.RIGHT));
    final JButton startButton = new JButton("Start");
    final JButton cancelButton = new JButton("Cancel");
    cancelButton.setEnabled(false);/*from  www . ja  v  a2  s.co  m*/
    buttonsArea.add(startButton);
    buttonsArea.add(cancelButton);
    // create the buttons area
    add(buttonsArea, BorderLayout.SOUTH);

    // build status area
    final JTextArea textArea = new JTextArea(5, 15);
    textArea.setEditable(false);
    JScrollPane statusScroll = new JScrollPane(textArea);
    add(statusScroll, BorderLayout.CENTER);

    // spawn a worker thread
    startButton.addActionListener(new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent e) {
        startButton.setEnabled(false);
        textArea.setText("");
        cancelButton.setEnabled(true);

        SwingWorker<Integer, Void> worker = new SwingWorker<Integer, Void>() {

          @Override
          protected Integer doInBackground() throws Exception {

            Thread.sleep(2000);
            int pk = new Random().nextInt();
            return pk;
          }

          @Override
          protected void done() {
            try {
              System.out.println("Primary key = " + get());
              textArea.setText("Primary key = " + get());
            } catch (InterruptedException | ExecutionException e) {
              e.printStackTrace();
            }
            startButton.setEnabled(true);
          }
        };
        worker.execute();
      }
    });

    // cancel button will kill worker and reset.
    cancelButton.addActionListener(new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent e) {
        startButton.setEnabled(true);
        cancelButton.setEnabled(false);
      }
    });

  }
}

public class Main {
  public static void main(String[] args) {
    // create frame for Main
    JFrame frame = new JFrame("java2s.com");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    frame.add(new MyPanel());
    frame.setSize(300, 250);
    frame.setVisible(true);
  }
}