Maintaining default locale in multi-lingual application

Question

Hello,
I have a multi-lingual application where the language can be changed at runtime.
To make the following code work properly, the default locale has to be set each
time the language changes. Why?
Since I need to check sometimes the platforms original locale (I do this with
"Locale.getDefault()"), I am looking for a way not to change the default locale,
but still to change the resourceBundle.
In the API I read under "ResourceBundle, Cache Management" that the bundles are cached. Is this the reason why redefining the resourceBundle has no effect? And if yes, how can it be avoided?
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
public class Y extends JFrame {
  boolean toggle;
  Locale currentLocale;
  JButton b;
  ResourceBundle languageBundle;
  String country, userLanguage;
  public Y() {
    setSize(300,300);
    setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    Container cp= getContentPane();
    b= new JButton();
    b.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent evt) {
     toggle= !toggle;
     if (toggle)
       country= "DE";
     else
       country= "GB";
     setUserLanguage(country);
    cp.add(b, BorderLayout.SOUTH);
    setUserLanguage("GB");
    setVisible(true);
  public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {
      public void run() {
     new Y();
  void setUserLanguage(String country) {
    if (country.equals("DE"))
      userLanguage= "de";
    else
      userLanguage= "en";
    currentLocale = new Locale(userLanguage, country);
//    System.out.println(currentLocale); // The locale changes ...
//    Locale.setDefault(currentLocale); // Remove comment slashes and it works.
//    languageBundle.clearCache(); // No effect.
    languageBundle = ResourceBundle.getBundle("MyBundle",currentLocale);
    System.out.println(languageBundle); // ... but the resourceBundle does not change.
    b.setText(languageBundle.getString("ButtonText"));
The resource bundle files:
MyBundle.properties
ButtonText= Just a button
MyBundle_de_DE.properties
ButtonText= Nur ein KnopfEdited by: Joerg22 on 18.08.2008 13:26

Answer 1

What's your default locale? If your default locale is de_DE, that's the expected behavior. The reason for it is the fallback mechanism searches default locale's bundle before falls back to the base bundle, i.e., in case of searching en_GB bundle, the search order is:
en_GB
en
de_DE
de
(base)
So, it will choose MyBundles_de_DE.
If you do not want this default locale fallback, you can specify ResourceBundle.Control instance, which is returned from ResourceBundle.Control.getNoFallbackControl() method, in your getBundle() call. Or if you do not use JDK6, you could copy the base bundle to MyBundles_en, which is ugly but should work.
Naoto
Edited by: naoto on Aug 18, 2008 1:05 PM