GUI Project Won't Compile

I'm doing a project and my code won't compile.

import javax.swing.*;
import java.awt.event.*;
public class BookStore extends JFrame{
private JPanel panel;
private JLabel question; //This will be where the question is.
private JTextField NumofBooks; //this is where the user will enter the number of books
private JButton OKButton,ClearButton,ExitButton; //Will give the user the points, cancel the points, and exit
private final int WINDOW_WIDTH = 310; //Need to make it visible
private final int WINDOW_HEIGHT = 100;

[code]....