Simples questao sobre GUI (mas preciso de uma ajudinha)

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JDesktopPane;
import javax.swing.JFrame;
import javax.swing.JInternalFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JSplitPane;
import javax.swing.JToolBar;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;


public class JanelaInicial extends JFrame{

	private JMenuBar barraFerramentas;
	private JPanel painelStatus;
	private JLabel barraStatus;
	private JMenu menu;
	private JPanel painelComponentesEsquerda;
	private JSplitPane splitPane;
	private JDesktopPane painelJanelas;
	
	public JanelaInicial(){
		super("Teste Layout");
		inicializarComponentes();
		setSize(800, 600);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
	}
	
	private void inicializarComponentes() {
		Container containerPrincipal = getContentPane();
		containerPrincipal.setLayout(new BorderLayout());
		criarBarraFerramentas(containerPrincipal);
		criarPaineisPrincipais(containerPrincipal);
		criarBarraStatus(containerPrincipal);
	}

	private void criarBarraFerramentas(Container containerPrincipal) {
		barraFerramentas = new JMenuBar();
		menu = new JMenu("Menu");
		JMenuItem item = new  JMenuItem("Item");
		menu.add(item);
		barraFerramentas.add(menu);
		setJMenuBar(barraFerramentas);
		JToolBar toolbar = new JToolBar();
		toolbar.add(new JButton("Teste"));
		containerPrincipal.add(toolbar, BorderLayout.PAGE_START);
	}

	private void criarPaineisPrincipais(Container containerPrincipal) {
		
		criarComponentesEsquerda();

		JDesktopPane painelJanelas = new JDesktopPane();
		JInternalFrame frameInterno = new JInternalFrame("Teste Frame Interno");
		painelJanelas.add(frameInterno);
		frameInterno.setVisible(true);
		frameInterno.setSize(new Dimension(200,200));

		splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
				painelComponentesEsquerda, painelJanelas);
		splitPane.setOneTouchExpandable(true);
		splitPane.setDividerLocation(150);
		Dimension minimumSize = new Dimension(100, 50);
		painelComponentesEsquerda.setMinimumSize(minimumSize);
		painelJanelas.setMinimumSize(minimumSize);
		containerPrincipal.add(splitPane,BorderLayout.CENTER);
		
	}


	private void criarComponentesEsquerda() {
		painelComponentesEsquerda = new JPanel();
		painelComponentesEsquerda.add(new JLabel("Aqui vão os componentes da esquerda"));
	}
	
	private void criarBarraStatus(Container containerPrincipal) {
		painelStatus = new JPanel(new FlowLayout(FlowLayout.LEFT));
		painelStatus.setBorder(BorderFactory.createBevelBorder(1));
		painelStatus.add(new JLabel("Status",SwingConstants.LEFT));
		Dimension d = painelStatus.getMaximumSize();
		containerPrincipal.add(painelStatus,BorderLayout.SOUTH);
	}
	
	public static void main(String[] args) {
		SwingUtilities.invokeLater(new Runnable() {
			@Override
			public void run() {
				new JanelaInicial().setVisible(true);
			}
		});
	}
	
	
}