- Use Sonar for tracking various metrics (it uses all well-known Open Source tools like PMD, Checkstyle, etc. and compatible with Hudson, which we already use in our projects);
- Use Cirr to document public API changes (to know when something really important has changed);
- Use Macker (btw, its' FAQ is really informative, thanks!) to keep dependencies between different modules under control. It first requires some modeling, after which it can break builds in case someone breaks convention;
The idea was inspired by one of the reports on Software Engineering Forum 2009 (link in Russian).