How to extract differences from similar programs? A cohesion metric approach

Merging similar programs is a promising solution to improve the maintainability of source code. Before merging programs, any syntactic difference has to be extracted as a new method. However, it is difficult for a developer to identify and extract differences from programs appropriately because he/she has to consider not only syntactic and semantic correctness but also the modularity of the programs after merging. In this paper, we propose a slice-based cohesion metrics approach to suggesting the extractions of differences from similar Java methods. This approach identifies syntactic differences from two methods, and then suggests sets of cohesive regions including those differences. The case study shows that the proposed approach can suggest refactorings that not only merge two methods but also increase the cohesiveness.