Practica de Java

package practica3;
import java.awt.BorderLayout;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JComboBox;
import javax.swing.JButton;
import java.awt.Dimension;
import javax.swing.JTextArea;
import java.awt.Rectangle;
import java.awt.Font;
public class RegistraProductos extends JFrame {
 private JPanel jContentPane = null;
 private JLabel jLabel = null;
 private JLabel jLabel1 = null;
 private JLabel jLabel2 = null;
 private JLabel jLabel3 = null;
 private JLabel jLabel4 = null;
 private JTextField jTextField = null;
 private JTextField jTextField1 = null;
 private JComboBox jComboBox = null;
 private JComboBox [...]