Share document model between JTextArea in Java

/*from   w w  w .  j  av  a2  s  .  c  o m*/
    
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.text.Document;

public class Main {
  public static void main(String args[]) {
    JFrame frame = new JFrame("Sharing Sample");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JTextArea textarea1 = new JTextArea();
    Document document = textarea1.getDocument();
    JTextArea textarea2 = new JTextArea(document);
    JTextArea textarea3 = new JTextArea(document);
    frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
    frame.add(new JScrollPane(textarea1));
    frame.add(new JScrollPane(textarea2));
    frame.add(new JScrollPane(textarea3));
    frame.setSize(300, 400);
    frame.setVisible(true);
  }
}