Aplikasi Toko Final

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class AplikasiToko2 extends JFrame{
    private JDesktopPane frmMDI;
    private JInternalFrame frmBarang, frmCustomer, frmUserAccount;
    private JPanel pnlBarang;
    private JPanel pnlCustomer;
    private JPanel pnlUserAccount;

    private JMenuBar MenuBar = new JMenuBar();
    private JMenu MenuMaster = new JMenu("Master Data");
    private JMenuItem MenuBarang = new JMenuItem("Barang");
    private JMenuItem MenuCustomer = new JMenuItem("Customer");
    private JMenuItem MenuUserAccount = new JMenuItem("User Account");
    private JMenu MenuTransaksi = new JMenu("Menu Transaksi");
    private JMenuItem MenuPenjualan = new JMenuItem("Penjualan");
    private JMenuItem MenuPembelian = new JMenuItem("Pembelian");
    private JMenu MenuExit = new JMenu("Exit");

    private static JLabel LblKodeBarang=new JLabel("Kode Barang");
    private static JTextField TxtKodeBarang=new JTextField();
    private static JLabel LblNamaBarang=new JLabel("Nama Barang");
    private static JTextField TxtNamaBarang=new JTextField();
    private static JLabel LblHargaBarang=new JLabel("Harga Barang");
    private static JTextField TxtHargaBarang=new JTextField();
    private static JButton TblBarangSave=new JButton("Save");
    private static JButton TblBarangCancel=new JButton("Cancel");
    private static JLabel LblNama=new JLabel("Nama Pelanggan");
    private static JTextField TxtNama=new JTextField();
    private static JLabel LblAlamat=new JLabel("Alamat");
    private static JTextField TxtAlamat=new JTextField();
    private static JButton TblBarangSave1=new JButton("Save");
    private static JButton TblBarangCancel1=new JButton("Cancel");
    private static JLabel LblUser=new JLabel("User");
    private static JTextField TxtUser=new JTextField();
    private static JLabel LblPassword=new JLabel("Password");
    private static JTextField TxtPassword=new JTextField();
    private static JButton BtnLogin=new JButton("Login");
    private static JButton BtnCancel=new JButton("Cancel");

    Dimension dimensi=Toolkit.getDefaultToolkit().getScreenSize();

    AplikasiToko2(){
        super("Aplikasi Toko");
        setSize(650,500);
        setLocation(dimensi.width/2-getWidth()/2, dimensi.height/2-getHeight()/2);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        frmMDI= new JDesktopPane();
        frmMDI.setLayout(null);
        this.add(frmMDI);

        MenuMaster.add(MenuBarang);
        MenuMaster.add(MenuCustomer);
        MenuMaster.addSeparator();
        MenuMaster.add(MenuUserAccount);
        MenuBar.add(MenuMaster);
        MenuTransaksi.add(MenuPenjualan);
        MenuTransaksi.add(MenuPembelian);
        MenuBar.add(MenuTransaksi);
        MenuBar.add(MenuExit);

        MenuBarang.addActionListener(new MenuHandler());
        MenuCustomer.addActionListener(new MenuHandler());
        MenuUserAccount.addActionListener(new MenuHandler());
        MenuTransaksi.addActionListener(new MenuHandler());
        MenuExit.addActionListener(new MenuHandler());
        TblBarangSave.addActionListener(new TombolHandler());
        TblBarangCancel.addActionListener(new TombolHandler());
        setContentPane(frmMDI);

        frmBarang=new JInternalFrame();
        frmBarang.setTitle("Master Data Barang");
        frmCustomer=new JInternalFrame();
        frmCustomer.setTitle("Master Data Customer");
        frmUserAccount=new JInternalFrame("Master Data UserAccount");

        pnlBarang=new JPanel();
        LblKodeBarang.setBounds(30,20,160,25);
        pnlBarang.add(LblKodeBarang);
        TxtKodeBarang.setBounds(120,20,100,25);
        pnlBarang.add(TxtKodeBarang);
        LblNamaBarang.setBounds(30,50,160,25);
        pnlBarang.add(LblNamaBarang);
        TxtNamaBarang.setBounds(120,50,200,25);
        pnlBarang.add(TxtNamaBarang);
        LblHargaBarang.setBounds(30,80,160,25);
        pnlBarang.add(LblHargaBarang);
        TxtHargaBarang.setBounds(120,80,100,25);
        pnlBarang.add(TxtHargaBarang);
        TblBarangSave.setBounds(80,160,80,25);
        pnlBarang.add(TblBarangSave);
        TblBarangCancel.setBounds(200,160,80,25);
        pnlBarang.add(TblBarangCancel);
        pnlBarang.setLayout(null);

        pnlCustomer=new JPanel();
        LblNama.setBounds(30,20,160,25);
        pnlCustomer.add(LblNama);
        TxtNama.setBounds(120,20,100,25);
        pnlCustomer.add(TxtNama);
        LblAlamat.setBounds(30,50,160,25);
        pnlCustomer.add(LblAlamat);
        TxtAlamat.setBounds(120,50,200,25);
        pnlCustomer.add(TxtAlamat);
        TblBarangSave1.setBounds(80,160,80,25);
        pnlCustomer.add(TblBarangSave1);
        TblBarangCancel1.setBounds(200,160,80,25);
        pnlCustomer.add(TblBarangCancel1);
        pnlCustomer.setLayout(null);

        pnlUserAccount=new JPanel();
        LblUser.setBounds(30,20,160,25);
        pnlUserAccount.add(LblUser);
        TxtUser.setBounds(120,20,100,25);
        pnlUserAccount.add(TxtUser);
        LblPassword.setBounds(30,50,160,25);
        pnlUserAccount.add(LblPassword);
        TxtPassword.setBounds(120,50,200,25);
        pnlUserAccount.add(TxtPassword);
        BtnLogin.setBounds(80,160,80,25);
        pnlUserAccount.add(BtnLogin);
        BtnCancel.setBounds(200,160,80,25);
        pnlUserAccount.add(BtnCancel);
        pnlUserAccount.setLayout(null);

        frmBarang.add(pnlBarang);
        frmCustomer.add(pnlCustomer);
        frmUserAccount.add(pnlUserAccount);

        frmMDI.add(frmBarang);
        frmMDI.add(frmCustomer);
        frmMDI.add(frmUserAccount);

        frmBarang.setBounds(10,10,367,250);
        frmCustomer.setBounds(30,30,367,250);
        frmUserAccount.setBounds(50,50,367,350);

        setJMenuBar(MenuBar);
        setVisible(true);
    }
        private class MenuHandler implements ActionListener{
            public void actionPerformed(ActionEvent e){
                JMenuItem X=(JMenuItem)e.getSource();
                if(X.getText().equals("Barang")){
                    frmBarang.setVisible(true);
                }else if(X.getText().equals("Customer")){
                    frmCustomer.setVisible(true);
                }else if(X.getText().equals("User Account")){
                    frmUserAccount.setVisible(true);
                }else if(X.getText().equals("Exit")){
                    dispose();
                }
            }
        }
        private class TombolHandler implements ActionListener{
            public void actionPerformed(ActionEvent e){
                JButton TblPilih=(JButton)e.getSource();
                if(TblPilih.getText().equals("Save")){
                    JOptionPane.showMessageDialog(null,"Pilih Save");
                    frmBarang.setVisible(false);
                }else if(TblPilih.getText().equals("Cancel")){
                    JOptionPane.showMessageDialog(null,"Pilih Cancel");
                    frmBarang.setVisible(false);
                }else if(TblBarangSave1.getText().equals("Save")){
                    JOptionPane.showMessageDialog(null,"Pilih Save");
                    frmCustomer.setVisible(false);
                }else if(TblBarangCancel1.getText().equals("Cancel")){
                    JOptionPane.showMessageDialog(null,"Pilih Cancel");
                    frmCustomer.setVisible(false);
                }else if(BtnLogin.getText().equals("Login")){
                    JOptionPane.showMessageDialog(null,"Pilih Login");
                    frmUserAccount.setVisible(false);
                }else if(BtnCancel.getText().equals("Cancel")){
                    JOptionPane.showMessageDialog(null,"Pilih Cancel");
                    frmUserAccount.setVisible(false);
                }
            }
        }
        public static void main(String[] args){
            AplikasiToko2 frameku=new AplikasiToko2();
        }
    }