The example shows how to localize JFileChooser.

Java Code:
public class LocalizeJFileChooser extends JPanel
   implements ActionListener {
   JButton go;
   AbstractButton button;
   ButtonGroup group;
   Locale locale;
   String msg ;

    protected JFileChooser z_chooser;
    String z_choosertitle;

  public LocalizeJFileChooser() {
    group = new ButtonGroup();

    locale = Locale.US;  // default value
    button = new JRadioButton("English", true);
    button.setActionCommand("en");
    button.addActionListener(this);
    group.add(button);
    add(button);

    button = new JRadioButton("Francais");
    button.setActionCommand("fr");
    button.addActionListener(this);
    group.add(button);
    add(button);

    go = new JButton("Do it");
    go.addActionListener(this);
    add(go);

    locale = Locale.US;

   }

 public void setUILanguage() {
   ResourceBundle rb;
   rb = ResourceBundle.getBundle("JFileChooser", locale);

   z_choosertitle = rb.getString("Title");

   UIManager.put
     ("FileChooser.lookInLabelText", 
        rb.getString("lookInLabelText"));
   UIManager.put
     ("FileChooser.filesOfTypeLabelText", 
        rb.getString("filesOfTypeLabelText"));
   UIManager.put
     ("FileChooser.upFolderToolTipText", 
        rb.getString("upFolderToolTipText"));
   }

  public void actionPerformed(ActionEvent e) {
    int result;

    if (e.getSource() instanceof JRadioButton) {
      if (e.getActionCommand().equals("en"))
         locale = Locale.US;
      else
         locale = Locale.FRANCE;
      setUILanguage();
      }
    else {
        z_chooser = new JFileChooser();
        z_chooser.setCurrentDirectory(new java.io.File("."));
        z_chooser.setDialogTitle(z_choosertitle);
        if (z_chooser.showOpenDialog(this) !=
              JFileChooser.APPROVE_OPTION)
            return;
        }
     }

  public Dimension getPreferredSize(){
    return new Dimension(200, 200);
    }

  public static void main(String s[]) {
    JFrame frame = new JFrame("");
    LocalizeJFileChooser panel = new LocalizeJFileChooser();
    frame.addWindowListener(
      new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
          System.exit(0);
          }
        }
      );
    frame.getContentPane().add(panel,"Center");
    frame.setSize(panel.getPreferredSize());
    frame.setVisible(true);
    }
}