contoh coding java GUI

package GUIae;
import java.util.Scanner;
public class GUI_dong extends javax.swing.JFrame {

    public GUI_dong() {
        initComponents();
    }
   
    private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {                                           
    Scanner masuk = new Scanner (System.in);
        int a;

    }                                          

    private void jTextField2ActionPerformed(java.awt.event.ActionEvent evt) {                                           
     Scanner masuk = new Scanner (System.in);
        int b; 
    }                                          

    private void jTextField2KeyPressed(java.awt.event.KeyEvent evt) {
        int panjang=Integer.parseInt(jTextField1.getText());
        int lebar=Integer.parseInt(jTextField2.getText());
        String hasil=String.valueOf(panjang*lebar);
        jLabel10.setText(hasil);
        String hasil2=String.valueOf(2*(panjang+lebar));
        jLabel11.setText(hasil2);
    }                                     

   
    public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new GUI_dong().setVisible(true);
            }
        });
    }

                        
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel10;
    private javax.swing.JLabel jLabel11;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JLabel jLabel5;
    private javax.swing.JLabel jLabel6;
    private javax.swing.JLabel jLabel7;
    private javax.swing.JLabel jLabel8;
    private javax.swing.JLabel jLabel9;
    private javax.swing.JPanel jPanel2;
    private javax.swing.JTextField jTextField1;
    private javax.swing.JTextField jTextField2;
                     
}