Java provides some built in Internationalization (I18N) functionality. Of course, since I know nothing about your project - Is it is a webapp, desktop app, etc. ?; How much I18N support you need (strings? Lots of strings? Just a few strings? Images? Layouts?)? - I'm not really sure how much more information would be useful...
Also not really sure how bar code printing and preparation fit into I18N... but this page should help provide some further information for you on using bar codes in Java.
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