This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
To this web application, we have to add internationalization(i18n) support for languages ike Spanish, French and later extend to other languages.
The server-side properties files are not available to the client, obviously. So as has been indicated, you'll need to do something on the server to create client-side resources that you can use. It can be a build-time solution, as Eric suggested, or can be an execution time, JSP-initiated solution.