Macker is a build-time architectural rule checking utility for Java developers. It's meant to model the architectural ideals programmers always dream up for their projects, and then break -- it helps keep code clean and consistent. You can tailor a rules file to suit a specific project's structure, or write some general "good practice" rules for your code. Macker doesn't try to shove anybody else's rules down your throat; it's flexible, and writing a rules file is part of the development process for each unique project.
Read more about what it does and what it's for in the very exciting FAQ. If your curiousity's piqued, skim the guide, or inspect a few simple examples.
It's free (GPL). You can download it and try it out.
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