Discovering Comprehension Pitfalls in Class Hierarchies

Despite many advances in program comprehension, polymorphism and inheritance are still the cause of many misunderstandings in object-oriented code. In this paper, we present a suite of such concrete, recurrent patterns where particular ways of using inheritance and polymorphism can easily mislead developers and maintainers during software understanding activities. We define these as comprehension pitfalls. Furthermore, the paper describes a metric-based approach aimed to automatically detect such situations in code. The experimental results presented in this paper, based on three medium-sized systems, indicate that the identified comprehension pitfalls and the approach used to detect them are a promising support for maintenance.