higher-kinded-j

Higher-kinded types, monads and composable effects for Java 25+: the Effect Path API for railway-style error handling, advanced optics (lens/prism/traversal) with code generation for records and sealed types, and Spring Boot integration. Maintained by higher-kinded-j on GitHub, where it has earned 78 stars from the community.

It's actively developed around annotation-processor, code-generation, effects, and is a solid reference for anyone building with these tools.