Characterizing the Usage, Evolution and Impact of Java Annotations in Practice
This study provides empirical insights for developers, researchers, and tool builders to improve Java annotation engineering, addressing a gap in practical knowledge.
The researchers conducted the first large-scale empirical study on Java annotations, analyzing 1,094 open-source projects to understand their usage, evolution, and impact on code quality, resulting in 10 novel findings.
Annotations have been formally introduced into Java since Java 5. Since then, annotations have been widely used by the Java community for different purposes, such as compiler guidance and runtime processing. Despite the ever-growing use, there is still limited empirical knowledge about the actual usage of annotations in practice, the changes made to annotations during software evolution, and the potential impact of annotations on code quality. To fill this gap, we perform the first large-scale empirical study about Java annotations on 1,094 notable open-source projects hosted on GitHub. Our study systematically investigates annotation usage, annotation evolution, and annotation impact, and generates 10 novel and important findings. We also present the implications of our findings, which shed light for developers, researchers, tool builders, and language or library designers in order to improve all facets of Java annotation engineering.