Java GUI : JFrame, JInternalFrame, JMenu to open two internal frame in same frame on JMenuItem clicked

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

class  softaid extends JFrame  implements  ActionListener 
{
  private JMenuItem AccOpen;
  private JMenuItem AccClose;
  private JDesktopPane desktop = new JDesktopPane();
  private JMenuBar  menuBar = new JMenuBar();
  static public  int MainWindowHeight=600;
  static  public  int MainWindowWidth=700;
		
  public softaid()
	  {
		  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		  setTitle("codeTpoint.com ");
		  setSize(700,600);
		  setLocation((Toolkit.getDefaultToolkit().getScreenSize().width  - getWidth()) / 2,
					(Toolkit.getDefaultToolkit().getScreenSize().height - getHeight()) / 2);
          setJMenuBar(menuBar);
		        
		  JMenu AccountMenu = new JMenu("Account");
		           
		  menuBar.add(AccountMenu);
		           
		  AccOpen = new JMenuItem("Open Account");
		  AccClose = new JMenuItem("Close Account");
		  
		  AccountMenu.add(AccOpen);
		  AccountMenu.add(AccClose);
	        
		  AccOpen.addActionListener(this);
		  AccClose.addActionListener(this);
			
		  getContentPane().add (desktop, BorderLayout.CENTER);
  
	      setVisible(true);
	  }
	  
	  
	  
	@Override
	public void actionPerformed(ActionEvent arg) {
		
		if(arg.getSource()==( JMenuItem) AccOpen)
		{
			OpenAccount oc= new OpenAccount(); 
			desktop.add(oc);
			oc.show();
    
		}
 	   if(arg.getSource()==( JMenuItem) AccClose)
		{
			closeAccount cc= new closeAccount(); 
			desktop.add(cc);
			cc.show();
		        
		}
	}

}
class OpenAccount extends JInternalFrame implements ActionListener
{
	private JPanel JP = new JPanel ();
	private JLabel lbl;
    private JButton btnOk;
	OpenAccount()
	{
		super ("Open New Account", false, true, false, true);
		setSize (500, 400);
		setLocation((softaid.MainWindowWidth-this.getSize().width)/2,(softaid.MainWindowHeight-this.getSize().height)/2);
		lbl = new JLabel ("Open Your Account window:");
		lbl.setForeground (Color.BLUE);
		lbl.setBounds (15, 15, 200, 120);
		btnOk = new JButton ("OK");
		btnOk.setBounds (50, 175, 100, 25);
		btnOk.addActionListener (this);
		JP.setLayout (null);
		JP.add(lbl);
		JP.add (btnOk);
		getContentPane().add (JP, BorderLayout.CENTER);
		setVisible (true);
	}

	@Override
	public void actionPerformed(ActionEvent arg) {
		Object obj = arg.getSource();

		if (obj == btnOk) {	
			
			JOptionPane.showMessageDialog (this, "You  are at open Account Window..");
    
		}

	}

}
class closeAccount extends JInternalFrame implements ActionListener
{
	private JPanel JP = new JPanel ();
	private JLabel lbl;
    private JButton btnOk;
    closeAccount()
	{
		super ("close Account", false, true, false, true);
		setSize (500, 400);
		setLocation((softaid.MainWindowWidth-this.getSize().width)/2,(softaid.MainWindowHeight-this.getSize().height)/2);
		lbl = new JLabel ("Open Your Account window:");
		lbl.setForeground (Color.RED);
		lbl.setBounds (15, 15, 200, 120);
		btnOk = new JButton ("OK");
		btnOk.setBounds (50, 175, 100, 25);
		btnOk.addActionListener (this);
		JP.setLayout (null);
		JP.add(lbl);
		JP.add (btnOk);
			
		getContentPane().add (JP, BorderLayout.CENTER);
		setVisible (true);
	}

	@Override
	   public void actionPerformed(ActionEvent arg) {
		Object obj = arg.getSource();
		if (obj == btnOk) {	
		JOptionPane.showMessageDialog (this, "You  are at close account window..");
		}

	}
	
}


class  win4
{
	  public  static void main(String popat[])
	  {
	   softaid win = new softaid(); 
  
	  }
}

Output-1

jj1

 

Output-2

jj2