Towards Understanding Programs by Counting Objects

A question familiar to any developer facing legacy code for the first time is, where to start? Understanding the entire code base of any large project is impractical, so techniques for identifying the most relevant code are needed. We discuss one potential technique, which we call "object counts:"' a report of the number of objects created during the execution of an object-oriented program. We show how object counts can help when comparing small designs, and comprehending a larger design—specifically JUnit. Our results indicate that the small amount of data provided by object counts can provide significant insight into a system's design.