Further Considerations about Relationship between Framework and Application Components

A large number of software applications are used over ten years, and are subjected to continuous maintenance activities to improve their operability, functionality, stability and so on. Through such maintenance activities, the internal structure of the software system becomes more complex. We believe that studying how the complexity has evolved is important for understanding the actual maintenance activities. In a previous experiment, we analyzed how code clones and use relations between application and framework components change through a longitudinal study of open source software. However, we performed our analysis over only one set of framework and application, so we would like to discuss how our findings generalize. In this paper, we replicate the previous experiment, targeting several open source projects. By comparing with the result of the past experiment, we will discuss about generalities of our findings. Moreover, we study the differences between the trends for both incoming and outgoing edges, how use relations increase and decrease through long term development, and how code clones are introduced in the software in the early period of the development. These analyses have a certain level of commonality for understanding actual developers' activities.