Abstract
In recent software development, repetitive code fragments (i.e., clones) are common due to the copy-and-paste programming practice, the framework-based development, or the reuse of same design patterns. Such similar code fragments are likely to introduce more bugs but are easily disregarded by a code reviewer or a programmer. In this paper, we present a code review tool to help code reviewers identify important code changes written by other programmers and recommend which changes need to be reviewed first. Specifically, to identify important code changes, our approach detects code clones across revisions and investigates them. Then, to help a code reviewer, our approach ranks the identified changes in accordance with several software quality metrics and statistics on those clones and changes. Furthermore, our approach allows the code reviewer to express their preferences during code review time. As a result, the code reviewer who has little knowledge of a code base can reduce his or her effort by reviewing the most significant changes that require an instant attention. To evaluate our approach, we integrated our approach with a modern IDE (e.g., Eclipse) as a plugin and then analyzed two third-party open source projects. The experimental results indicate that our approach can improve code reviewer's productivity.