Adding a scroll bar to my text area

Question

I just want to know how to add a scroll bar to my text area. The text that is inputted by the reader goes on for more than the area goes and a scroll bar doesn't automatically come up.

Here is my entire code:

import java.awt.EventQueue;
import java.io.FileReader;
import java.io.IOException;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.border.EmptyBorder;

public class HGU3N extends JFrame {

private static final long serialVersionUID = 1L;
private JPanel contentPane;

public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                HGU3N frame = new HGU3N();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

public HGU3N() throws IOException {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 895, 493);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);

    JTextArea textArea = new JTextArea();
    FileReader reader = new FileReader("Notes\\HumanGeoUnit3Notes.txt");
    textArea.read(reader,"Notes\\HumanGeoUnit3Notes.txt");
    textArea.setBounds(10, 11, 859, 432);
    textArea.setLineWrap(true);
    textArea.setEditable(false);
    contentPane.add(textArea);
}

}