Developing component based software is cool. But which of the developed components are actually used?
Most of the time it is uncertain. A similar uncertainty emerges with regression tests. Are the bug-fixes actually tested?
To some developers these information might not be interesting. As much more it is for decision makers.
We use JaCoCo for gathering this usage/test data.
With a little package-component-mapping we can get more certainty, whether which component is actually used, or tested. With additional report formatting it is easy to understand. Even management could comprehend.