Internationalization in Java - An Introduction

Sun defines 'Internationalization' as the process of designing an application so that it can be adapted to various languages and regions without engineering changes. Sometimes the term internationalization is abbreviated as i18n, because there are 18 letters between the first "i" and the last "n.". Let's write a simple Java program to say Hello to a person and Welcome that person to India, in different languages. Here are the steps to Internationalize a program:
(a) Create the .properties files:The English version of the .properties file is say MessagesBundle.properties and contains

greetings = Hello
welcome = Welcome to India

The same contents would be there in the file MessagesBundle_en_US.properties. To create the .properties files in other languages, I am making use of the free, online Free2Professional Site.
Here's the German version of the .properties file ie. MessagesBundle_de_DE.properties where de is the language code and DE is the country code. The contents of this file is:

greetings = Hallo
welcome = Willkommen in Indien

(b) Define the Locale The Locale object identifies a particular language and country. The program gets the Language and Country code from the command line. Thus,

String lang = new String(args[0]);
String country = new String(args[1]);
Locale cLocale = new Locale(lang, country);

(c) Create a Resource Bundle: The ResourceBundle objects contain locale-specific objects. It is created as:

ResourceBundle msg = 
  ResourceBundle.getBundle("MessagesBundle", cLocale);

(d) Fetch the Text from the ResourceBundle: To retrieve the message identified by the welcome key, you invoke getString as follows:

String msg = msg.getString("welcome");

Well, that's all that's required. Here's the full code:

import java.util.*;
public class InternationalizationEx
{
  public static void main(String[] args)
  {
    String lang, country;
    Locale cLocale;
    ResourceBundle msg;

    if (args.length != 2)
    {
      lang = new String("en");
      country = new String("US");
    }
    else
    {
      lang = new String(args[0]);
      country = new String(args[1]);
    }

    cLocale = new Locale(lang, country);
    msg = ResourceBundle.getBundle("MessagesBundle", cLocale);

    System.out.println(msg.getString("greetings"));
    System.out.println(msg.getString("welcome"));
  }
}

To run the program, open a DOS window and type:

java InternationalizationEx de DE

Note: Ensure that the three .properties files and the .java program are in the same folder.

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