Currently, the I18n framework checks for duplicate or missing messages in the property files. This check is very nice to have, but throwing an exception often causes problems in many different tests. Given that some of these tests may wrap the exception thrown by the I18n class, some of these failures can be very difficult to track down.

It would be better to have each I18n class (e.g., "CoreI18n") record the problems, and to create a test case for each of these classes. The test case can verify that there are no problems. Then, if there is a problem in a properties file, the test will fail while other tests (that don't necessarily care so much about missing or duplicate messages) won't.