RotatableWord homework

package WordModelView;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
/** RotatableWord represents a single word that can be "rotated"
 *  left or right.
 */
public class RotatableWord extends JFrame implements ActionListener
{
   public static void main(String [] args)
   {
       RotatableWord app = new RotatableWord("exhilaration");

   }

    private JLabel wordLabel = new JLabel();
    private JButton left;
    private JButton right;
    private String theWord;

    public RotatableWord(String letters)
    {
        this.theWord = letters;
        wordLabel.setText(theWord);
        getContentPane().add(wordLabel);
        left = new JButton("<");
        right = new JButton(">");
        left.addActionListener(this);
        right.addActionListener(this);
        setLayout(new FlowLayout());
        getContentPane().add(left);
        getContentPane().add(right);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLocation(0,100);
        pack();
        setVisible(true);
    }

    public void actionPerformed(ActionEvent evt)
    {
        if (evt.getSource() == left)
        {
           goLeft();
        }
        if (evt.getSource() == right)
        {
           goRight();
        }
        // display the updated word
        wordLabel.setText(theWord);
    }


    /** Rotate the word to the left */
    public void goLeft()
    {
        theWord = theWord.substring(1) + theWord.charAt(0);
    }
    /** Rotate the word to the right */
    public void goRight()
    {
        theWord = theWord.charAt(theWord.length()-1) + theWord.substring(0,theWord.length()-1);
    }
}