Fast, Easy Unit Tests
Once these setup steps are done, you will find that writing unit tests with Jython is much faster and requires less code than with Java. The original goal of Python was to be a scripting language; Jython enables you to script your Java applications, and it eases the task of writing tests.
This article demonstrated how to integrate Jython tests into Eclipse and its JUnit plugin. It could have shown how to integrate it into an Ant task, or any other tool that enables test running. That technology improves greatly the programmer's productivity.
Now, wouldn't enabling C-Python testing from the JUnit Eclipse framework be great? It would enable Eclipse to become an IDE with cross-language, on-the-fly testing integration. It's not as difficult as it seems; it requires code generation, but that's a topic for another article.