import java.awt.Container;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class SharedModel {
public static void main(String[] args) {
JFrame frame = new JFrame("Shared Model");
JTextArea areaFiftyOne = new JTextArea();
JTextArea areaFiftyTwo = new JTextArea();
areaFiftyTwo.setDocument(areaFiftyOne.getDocument());
JTextArea areaFiftyThree = new JTextArea();
areaFiftyThree.setDocument(areaFiftyOne.getDocument());
frame.setLayout(new GridLayout(3, 1));
frame.add(new JScrollPane(areaFiftyOne));
frame.add(new JScrollPane(areaFiftyTwo));
frame.add(new JScrollPane(areaFiftyThree));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 300);
frame.setVisible(true);
}
}