How do annotations affect Java code readability?

Eduardo Guerra, Everaldo Gomes, Jeferson Ferreira, Igor Wiese, Phyllipe Lima, Marco Gerosa, Paulo Meirelles

Research output: Contribution to journalArticlepeer-review


Context: Code annotations have gained widespread popularity in programming languages, offering developers the ability to attach metadata to code elements to define custom behaviors. Many modern frameworks and APIs use annotations to keep integration less verbose and located nearer to the corresponding code element. Despite these advantages, practitioners’ anecdotal evidence suggests that annotations might negatively affect code readability. Objective: To better understand this effect, this paper systematically investigates the relationship between code annotations and code readability. Method: In a survey with software developers (n=332), we present 15 pairs of Java code snippets with and without code annotations. These pairs were designed considering five categories of annotation used in real-world Java frameworks and APIs. Survey participants selected the code snippet they considered more readable for each pair and answered an open question about how annotations affect the code’s readability. Results: Preferences were scattered for all categories of annotation usage, revealing no consensus among participants. The answers were spread even when segregated by participants’ programming or annotation-related experience. Nevertheless, some participants showed a consistent preference in favor or against annotations across all categories, which may indicate a personal preference. Our qualitative analysis of the open-ended questions revealed that participants often praise annotation impacts on design, maintainability, and productivity but expressed contrasting views on understandability and code clarity. Conclusions: Software developers and API designers can consider our results when deciding whether to use annotations, equipped with the insight that developers express contrasting views of the annotations’ impact on code readability.

Original languageEnglish (US)
Article number62
JournalEmpirical Software Engineering
Issue number3
StatePublished - May 2024


  • Code annotations
  • Code readability
  • Program comprehension
  • Software engineering

ASJC Scopus subject areas

  • Software


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