Deep learning based feature envy detection

Software refactoring is widely employed to improve software quality. A key step in software refactoring is to identify which part of the software should be refactored. To facilitate the identification, a number of approaches have been proposed to identify certain structures in the code (called code smells) that suggest the possibility of refactoring. Most of such approaches rely on manually designed heuristics to map manually selected source code metrics to predictions. However, it is challenging to manually select the best features, especially textual features. It is also difficult to manually construct the optimal heuristics. To this end, in this paper we propose a deep learning based novel approach to detecting feature envy, one of the most common code smells. The key insight is that deep neural networks and advanced deep learning techniques could automatically select features (especially textual features) of source code for feature envy detection, and could automatically build the complex mapping between such features and predictions. We also propose an automatic approach to generating labeled training data for the neural network based classifier, which does not require any human intervention. Evaluation results on open-source applications suggest that the proposed approach significantly improves the state-of-the-art in both detecting feature envy smells and recommending destinations for identified smelly methods.