Me ajudem com este erro

import javax.swing.JDesktopPane;

import javax.swing.JTextPane;

import javax.swing.JButton;

public class Teste {

int a=0;
private JDesktopPane jDesktopPane = null;  
private JTextPane jTextPane = null;
private JButton jButton = null;


public static void main(String[] args) {
	Teste test = new Teste();
	test.[b]setVisible[/b](true);
}

public Teste(){
	[b]super("Teste");[/b]
	montarLayout();
}

public void montarLayout(){
	this.[b]setjDesktopPane[/b](getJDesktopPane());		
}

private JDesktopPane getJDesktopPane() {
	if (jDesktopPane == null) {
		jDesktopPane = new JDesktopPane();
		jDesktopPane.setSize(504, 163);
		jDesktopPane.setBackground(java.awt.Color.lightGray);
		jDesktopPane.add(getJTextPane(), null);
		jDesktopPane.add(getJButton(), null);
	}
	return jDesktopPane;
}

private JTextPane getJTextPane() {
	if (jTextPane == null) {
		jTextPane = new JTextPane();
		jTextPane.setBounds(42, 33, 166, 22);
		jTextPane.setText("O valor de a é: " +a);
	}
	return jTextPane;
}
 
private JButton getJButton() {
	if (jButton == null) {
		jButton = new JButton();
		jButton.setBounds(292, 64, 91, 25);
		jButton.setText("Click aqui");
		jButton.addMouseListener(new java.awt.event.MouseAdapter() { 
			public void mouseClicked(java.awt.event.MouseEvent e) {    
				a +=1;
				jTextPane.setText("O novo valor de a é: " + a);// TODO Auto-generated Event stub mouseClicked()
			}
		});
	}
	return jButton;
}