`

    import java.awt.*;
    import javax.swing.*;
    import java.awt.event.*;
    import java.net.URL;
    import javax.swing.JDesktopPane;
    import javax.swing.JFrame;
    import javax.swing.JInternalFrame;
    import javax.swing.JMenu;
    import javax.swing.JMenuBar;
    import javax.swing.JMenuItem;
    import javax.swing.JOptionPane;
    import javax.swing.SwingUtilities;

    public class Main1 extends JFrame{

    JDesktopPane jdpDesktop;


    public Main1() {

        JFrame frame = new JFrame("MainForm");

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jdpDesktop = new JDesktopPane() {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(600, 600);
            }
        }; 

        createFrame();

        frame.setContentPane(jdpDesktop);

        frame.setJMenuBar(createMenuBar());

        frame.pack();
        frame.setVisible(true);
    }

     JMenuBar createMenuBar() {
        JMenuBar menuBar = new JMenuBar();
           JMenu menu = new JMenu("Settings");
        JMenuItem menuItem = new JMenuItem("Logout");
        menuItem.setMnemonic(KeyEvent.VK_N);
        menuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                 JOptionPane.showMessageDialog(
                        null,
                        "Thank You",
                        "Logout", JOptionPane.PLAIN_MESSAGE
                        );
            }
        }); 
        menu.add(menuItem);
        menuBar.add(menu);
        return menuBar;
    }

    protected void createFrame() {
        MyInternalFrame frame = new MyInternalFrame();
        frame.setVisible(true); jdpDesktop.add(frame);

    }

    class MyInternalFrame extends JInternalFrame {

        static final int xPosition = 150, yPosition = 140;

        public MyInternalFrame() {
            super("Calculator" ,  true,
                    true, 
                    true, 
                    true);
            setSize(300, 300);
            // Set the window's location.
            setLocation(xPosition , yPosition
                    );

        setLayout(null);
        getContentPane().setBackground(Color.white);

        }   
    }




     public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Main1();
            }
        });
    }
}

how to add toolbar?

`

I like the style of using factory methods that build and return a menu bar or other complex components. Nothing wrong with it at all IMHO. It certainly makes the code easier to read and understand.