Java JTextArea set caret position

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;

import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class Main extends JPanel {
  JTextArea textArea = new JTextArea();
  JScrollPane scrollPane = new JScrollPane(textArea);
  public Main() {
    super(new BorderLayout());
    textArea.setEditable(false);//from w  ww  .jav  a 2 s  .  co  m
    
    scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
    scrollPane.setPreferredSize(new Dimension(400, 250));
    add(scrollPane, BorderLayout.CENTER);
    textArea.append("scroll mouse, mouse");
    
    textArea.setCaretPosition(textArea.getDocument().getLength());
    
    setPreferredSize(new Dimension(450, 350));
    setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
  }

  public static void main(String[] args) {
    JFrame frame = new JFrame("MouseWheelEventDemo");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JComponent newContentPane = new Main();
    newContentPane.setOpaque(true); // content panes must be opaque
    frame.setContentPane(newContentPane);

    frame.pack();
    frame.setVisible(true);
  }
}