Java Swing How to - Handle Caret event with CaretListener for JTextArea

Question

We would like to know how to handle Caret event with CaretListener for JTextArea.
Answer

/*  w  w  w .  j a  va 2  s.  c  om*/
import java.awt.BorderLayout;
import java.awt.Container;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;

public class CaretSample {
  public static void main(String args[]) {
    JFrame frame = new JFrame("Caret Example");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container content = frame.getContentPane();
    JTextArea textArea = new JTextArea();
    JScrollPane scrollPane = new JScrollPane(textArea);
    content.add(scrollPane, BorderLayout.CENTER);

    final JTextField dot = new JTextField();
    dot.setEditable(false);
    JPanel dotPanel = new JPanel(new BorderLayout());
    dotPanel.add(new JLabel("Dot: "), BorderLayout.WEST);
    dotPanel.add(dot, BorderLayout.CENTER);
    content.add(dotPanel, BorderLayout.NORTH);

    final JTextField mark = new JTextField();
    mark.setEditable(false);
    JPanel markPanel = new JPanel(new BorderLayout());
    markPanel.add(new JLabel("Mark: "), BorderLayout.WEST);
    markPanel.add(mark, BorderLayout.CENTER);
    content.add(markPanel, BorderLayout.SOUTH);

    CaretListener listener = new CaretListener() {
      public void caretUpdate(CaretEvent caretEvent) {
        dot.setText("" + caretEvent.getDot());
        mark.setText("" + caretEvent.getMark());
      }
    };

    textArea.addCaretListener(listener);

    frame.setSize(250, 150);
    frame.setVisible(true);
  }
}