JInternalFrame maximizado

package apresentacao;

import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JDesktopPane;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;

public class menuPrincipal extends JFrame  implements ActionListener{
JDesktopPane desktop = new JDesktopPane();
public static JFrame mn = new menuPrincipal();
JMenu arqMenu;
JMenuItem consulta, medico, paciente, ajuda;
JMenuBar barra;

public menuPrincipal() 
{
	setSize(0,0);
	setLocationRelativeTo(null);
	setResizable(true);
	setContentPane(desktop);
	setExtendedState(JFrame.MAXIMIZED_BOTH);


	arqMenu = new JMenu("Arquivo");
	arqMenu.setMnemonic('A');
	
	consulta = new JMenuItem("Consulta");
	consulta.setMnemonic('R');
	consulta.addActionListener(this);
	arqMenu.add(consulta);

	medico = new JMenuItem("Medico");
	medico.setMnemonic('M');
	medico.addActionListener(this);
	arqMenu.add(medico);

	paciente = new JMenuItem("Paciente");
	paciente.setMnemonic('M');
	paciente.addActionListener(this);
	arqMenu.add(paciente);
	
	barra = new JMenuBar();

	barra.setSize(500,20);
	barra.setLocation(0,0);
	barra.add(arqMenu);
	
	ajuda =  new JMenuItem("ajuda");
	ajuda.setMnemonic('M');
	ajuda.addActionListener(this);
	arqMenu.add(ajuda);
	
	
	getContentPane().setLayout(null);
	desktop.setDragMode(JDesktopPane.OUTLINE_DRAG_MODE);
	telaLoginInternal frame = new telaLoginInternal();
	try {
		frame = new telaLoginInternal();
	} catch (Exception e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	   getContentPane().add(barra);
	


	desktop.add(frame);

	frame.setVisible(true);
}

	public static void main(String[] args) throws Exception {
	
mn.show();

mn.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
menuPrincipal app =  new menuPrincipal();
app.addWindowListener
(
		new WindowAdapter() 
		{
			public void windowClosing (WindowEvent e)
			{
				System.exit(0);
			}
		}
);
	}

	public void actionPerformed(ActionEvent arg0) {
		// TODO Auto-generated method stub
		if(arg0.getSource()==ajuda)
		{
			int w = getWidth(); 
		System.out.println(w);
		}
	}

}

package apresentacao;
import java.awt.Cursor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyVetoException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.ParseException;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JInternalFrame;
import javax.swing.JLabel;
import javax.swing.JPasswordField;
import javax.swing.event.ChangeListener;
import javax.swing.text.MaskFormatter;

import negocios.TamanhoMaximo;
public class telaLoginInternal extends JInternalFrame implements ActionListener{
	JFormattedTextField txtLogin;
	JPasswordField txtSenha;
	JLabel labelSenha, labelLogin;
	static JButton botaoOk;
	JButton botaoSair;
	ImageIcon b1, b2;
	MaskFormatter teste;
	String tipo="", usuario="", senha="";
	static int openFrameCount = 0;
	static final int xOffset = 30, yOffset = 30;
	
	 
	public telaLoginInternal()
	{
		super("TelaLogin"+(++openFrameCount),true, true, true, true);
		setSize(400,220);

		//addPropertyChangeListener(IS_MAXIMUM_PROPERTY, null);
		setDefaultCloseOperation(JInternalFrame.EXIT_ON_CLOSE);

		setOpaque(true);
		try {
			setMaximum(true);
		} catch (PropertyVetoException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}
		labelLogin = new JLabel("Login:");
		labelLogin.setLocation(100,30);
		labelLogin.setSize(100,20);
		getContentPane().add(labelLogin);
		
		try {
            teste = new MaskFormatter("#,###,###.00");
        } catch (ParseException e) {
            // TODO Auto-generated catch block
         System.out.println("AAAA");
        }
        
        teste.setValidCharacters("[telefone removido]");
        txtLogin = new JFormattedTextField(teste);
        txtLogin.setComponentOrientation(java.awt.ComponentOrientation.RIGHT_TO_LEFT);
		txtLogin.setSize(140,20);
		txtLogin.setLocation(150,30);
		txtLogin.setCursor(new Cursor(Cursor.TEXT_CURSOR));  
		getContentPane().add(txtLogin);
		
		labelSenha = new JLabel("Senha");
		labelSenha.setSize(100,20);
		labelSenha.setLocation(100,60);
		getContentPane().add(labelSenha);
		
		txtSenha = new JPasswordField();
		txtSenha.setSize(140,20);
		txtSenha.setLocation(150,60);
		txtSenha.setCursor(new Cursor(Cursor.TEXT_CURSOR));  
		getContentPane().add(txtSenha);
		
		b1 = new ImageIcon("Login");
		botaoOk = new JButton("Login");
		botaoOk.setSize(100,60);
		botaoOk.setLocation(170,100);
		botaoOk.addActionListener(this);
		botaoOk.setCursor(new Cursor(Cursor.HAND_CURSOR));  
		getContentPane().add(botaoOk);
		 setLocation(xOffset*openFrameCount, yOffset*openFrameCount);
		 setLayout(null);
	}


	public void actionPerformed(ActionEvent arg0) {
		// TODO Auto-generated method stub
		if(arg0.getSource()==botaoOk){
	String DNS = "jdbc:odbc:bdtcc";
			
			try
			{
				Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
				Connection conexao = DriverManager.getConnection(DNS);
				Statement st = conexao.createStatement();
				ResultSet rs = st.executeQuery("SELECT * FROM Usuario Where Login = '"+txtLogin.getText()+"' and Senha = '"+txtSenha.getText()+"'");
				rs.next();
				usuario = rs.getString("Login");
				senha = rs.getString("Senha");
				tipo = rs.getString("Usuario");
				conexao.close();
				
				if(tipo.equals("administrador")){
					System.out.println("porrrra");
				}else if(tipo.equals("comum"))
					System.out.println("A");
			
				//System.out.println(usuario+senha+usuario);
			}catch(SQLException ex)
			{
			System.out.println("Usuário ou Senha Inválidos!");
			} catch (ClassNotFoundException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
}

try {   
        setMaximum(true);   
    } catch (PropertyVetoException e1) {   
        // TODO Auto-generated catch block   
        e1.printStackTrace();   
    }

desktop.add(frame);   
    try {
	    frame.setMaximum(true);
	} catch (Exception e) {
		// TODO: handle exception
	}
    frame.setVisible(true);