Re:Duvida

import java.awt.GridLayout;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.text.NumberFormat;
import java.util.Locale;

import javax.swing.JFrame;
import javax.swing.JTextField;


public class JTextFieldFormat extends JFrame {

	private JTextField txtSaldo;
	private JTextField txtNome;
	
	public JTextFieldFormat(){
		super("Teste Focus");
		setLayout(new GridLayout(3,1));

		txtSaldo = new JTextField();
		txtNome = new JTextField();
		
		getContentPane().add(txtSaldo);
		getContentPane().add(txtNome);
		
		txtSaldo.addFocusListener(listener);

		pack();
		setVisible(true);
	}
	
	public FocusAdapter listener = new FocusAdapter(){
	    public void focusLost(FocusEvent e){
	    	try {
		    	NumberFormat nf = NumberFormat.getInstance(new Locale("pt","BR"));
		    	nf.setMaximumFractionDigits(2);
		    	nf.setMinimumFractionDigits(2);
		    	String valueStr = txtSaldo.getText();
		    	if(!valueStr.equals("")){
			    	Number value = nf.parse(txtSaldo.getText());
			    	txtSaldo.setText(nf.format(value));
		    	}
			} catch (Exception ex) {
				System.out.println(ex);
			}
	    }
	};

	public static void main(String[] args) {
		new JTextFieldFormat();

	}

}