Java Localization Practices

1. What is Localization?

Localization in Java involves adapting your application to support different languages, regions, and formats using the Locale and ResourceBundle classes.

2. Locale Strings

Language and Country Codes

A Locale object identifies a specific region using a combination of language code (ISO 639) and country code (ISO 3166).

import java.util.Locale;

public class LocaleExample {
    public static void main(String[] args) {
        Locale localeUS = new Locale("en", "US");
        Locale localeFR = new Locale("fr", "FR");
        
        System.out.println("Locale US: " + localeUS);
        System.out.println("Locale FR: " + localeFR);
    }
}
        

Using Locale.Builder

The Locale.Builder class provides a flexible way to construct Locale objects.

import java.util.Locale;

public class LocaleBuilderExample {
    public static void main(String[] args) {
        Locale locale = new Locale.Builder()
                          .setLanguage("en")
                          .setRegion("GB")
                          .build();
        System.out.println("Locale: " + locale);
    }
}
        

N.B : In Java, constructors are simple for initialization but become cumbersome with many parameters, while the Builder pattern offers flexibility, clarity, and better handling of complex or optional attributes.

3. Resource Bundles

ResourceBundle helps load property files for specific locales.

Example of ResourceBundle

import java.util.Locale;
import java.util.ResourceBundle;

public class ResourceBundleExample {
    public static void main(String[] args) {
        Locale localeFR = new Locale("fr", "FR");
        ResourceBundle bundle = ResourceBundle.getBundle("Messages", localeFR);
        
        System.out.println(bundle.getString("greeting"));
    }
}
        

Properties File Example (Messages_fr.properties):

greeting=Bonjour!
        

By using Locale and ResourceBundle, developers can build applications that adapt to global users effectively.