RepliComment: Identifying Clones in Code Comments

TL;DR

RepliComment is a tool that automatically detects clone comments in Java code, helping developers identify copy-paste errors and poorly written comments to improve documentation quality.

Contribution

It introduces a novel automated approach for detecting comment clones in Java projects, surpassing previous methods in accuracy and scope.

Findings

Identified over 11,000 comment clones in 10 Java projects.

Detected more than 1,300 potentially critical comment clones.

Achieved 79% precision in manual validation of critical clones.

Abstract

Code comments are the primary means to document implementation and facilitate program comprehension. Thus, their quality should be a primary concern to improve program maintenance. While much effort has been dedicated to detecting bad smells, such as clones in code, little work has focused on comments. In this paper we present our solution to detect clones in comments that developers should fix. RepliComment can automatically analyze Java projects and report instances of copy-and-paste errors in comments, and can point developers to which comments should be fixed. Moreover, it can report when clones are signs of poorly written comments. Developers should fix these instances too in order to improve the quality of the code documentation. Our evaluation of 10 well-known open source Java projects identified over 11K instances of comment clones, and over 1,300 of them are potentially critical. We improve on our own previous work, which could only find 36 issues in the same dataset. Our manual inspection of 412 issues reported by RepliComment reveals that it achieves a precision of 79% in reporting critical comment clones. The manual inspection of 200 additional comment clones that RepliComment filters out as being legitimate, could not evince any false negative.