GSoC 2026 Proposal — Extending Checkstyle for Java 17–21 Features (Records, Sealed Classes, Pattern Matching)

[Sharanya Mahajan]

Hello Checkstyle Community! 

My name is Sharanya Mahajan, a second-year Computer Science student from Ramdeobaba University, Nagpur, India. I have submitted a GSoC 2026 proposal for Checkstyle and wanted to introduce myself and share my idea to get early feedback from the community.

What I am proposing: Implementing 12 new checks targeting modern Java features introduced in Java 17–21 — specifically Records, Sealed Classes, Pattern Matching, Text Blocks, and Switch Expressions — organized into four modules: RecordModule, SealedClassModule, PatternMatchingModule, and ModernSyntaxModule.

Why I think this matters: Teams migrating to Java 17+ currently have no automated way to enforce style rules on these constructs inside Checkstyle. This gap forces developers to rely on informal code review for things that could and should be caught statically.

What I have done so far: I have built Checkstyle locally from source, studied the DetailAST API and existing checks in the coding package, and written draft implementations for several of the proposed checks to validate my approach before submitting.

I would love any feedback on the direction, scope, or technical approach — especially from maintainers who know where the codebase is headed. I am fully committed to following contribution standards and iterating based on your guidance.

Happy to share draft check code or answer any questions!

Thank you for building and maintaining such an impactful tool. 🙏

GitHub: github.com/sharanyamahajan Timezone: IST (GMT+5:30)

— Sharanya Mahajan