1. Reading

  • Horstmann, Ed 11, Vol I, chapter 7.5

  • Horstmann, Ed 11, Vol II, chapter 7

2. Additional Pointers

  • If you haven’t read the Horstmann book but you need an introduction into Internationalization, read this tutorial from DZONE here. Make sure to read the bit about Resource Bundles, as you use them in the exercise for this week.

3. Exercises

Exercise 1: In the pub (Spanish beer)

In the pub Spanish

For this exercise, you are expanding on the pub exercise again. This time, enums and exceptions are all implemented and tested. The focus this week is on Internationalization! We want to make sure that the pub can run in different languages.

Open the project folder in Netbeans. Let’s first look at the resources of the project. You will notice a bunch of new files in the resources folder. The files contain the translations of error messages into Dutch, German and Spanish. For example, the inthepub_nl_NL.properties file contains

You\ drank\ too\ much=U hebt te veel gedronken
You\ are\ too\ young\ to\ drink=Je bent te jong voor drank
We\ are\ sold\ out=Wij zijn uitverkocht

So when the pub raises an EmptyStockException and the Locale is Dutch, it should display the Dutch error message, not the English one. You don’t need to touch the language properties files, unless you want to add more languages (or perhaps our Spanish is too horrible!).

In this exercise you work on three files:

  1. LanguageTest.java, which is your main file for testing your implementation. Remember, work test-driven! What you should check is that the Exceptions are thrown with a message in the correct language.

  2. PubException.java, this is a new Exception that all other Exceptions inherit. It is the one responsible for translating the error messages. Your implementation goes here.

  3. HablasEspañol.java, which provides a main method for you to play around with the languages. Feel free to change this code to your liking to familiarize yourself with Internationalization, it is not tested.

If you want to run the program, you can use the run.sh file that we provided in the project’s repository. Simply execute it to test the pub simulation. Alternatively, simply type java -Duser.language=nl -Duser.country=NL -cp target/classes/ pub.ParlezEspañol in your command line interface. Of course, this will throw errors as long as you haven’t written your implementation!

Where should I start?

Start with the PubException.java class and implement the constructor so that the compilor errors will go away. Then, move to LanguageTest.java and work on the rest of the exercise, first writing the tests and then implementing in the PubException class.


There are some inconsistencies in the property bundle files. The keys should be the same and they are not.

The following keys are to be used. Please adapt the property files and or the test and source code where appropriate.

You\ drank\ too\ much
You\ are\ too\ young\ to\ drink
We\ are\ sold\ out

in particular beer\ is\ sold\ out is wrong.

The key and values are actually missing from the default properties as well.

Corrected inthepub.properties properties
You\ drank\ too\ much=You drank too much
You\ are\ too\ young\ to\ drink=You are too young to drink
We\ are\ sold\ out=We are sold out
Windows run command
@echo off
rem @author David Greven - https://github.com/grevend
if not exist target/classes call mvn clean compile
chcp 65001
java -Duser.language=nl -Duser.country=NL -cp target/classes/ pub.HablasEspañol
java -Duser.language=es -Duser.country=ES -cp target/classes/ pub.HablasEspañol

3.1. Test run reports Week 7