Recovering the Evolution Stable Part Using an ECGM Algorithm: Is There a Tunnel in Mozilla?

Analyzing the evolutionary history of the design of object-oriented software is an important and difficult task where matching algorithms play a fundamental role. In this paper, we investigate the applicability of an error-correcting graph matching (ECGM) algorithm to object-oriented software evolution. By means of a case study, we report evidence of ECGM applicability in studying the Mozilla class diagram evolution. We collected 144 Mozilla snapshots over the past six years, reverse-engineered class diagrams and recovered traceability links between subsequent class diagrams. Our algorithm allows us to identify evolving classes that maintain a stable structure of relations(associations, inheritances and aggregations) with other classes and thus likely constitute the backbone of Mozilla.