Review and improve Java code using comprehensive generics best practices that enforce compile-time type safety and enable flexible, reusable APIs.
Prerequisites: Run ./mvnw compile or mvn compile before applying any change. If compilation fails, stop immediately and do not proceed — compilation failure is a blocking condition.
Core areas: Type safety (avoiding raw types, eliminating unsafe casts), code reusability (generic methods and types for multiple type contexts), API clarity (PECS wildcards — ? extends for producers, ? super for consumers), performance optimization (eliminating boxing/casting overhead), diamond operator for type inference, type erasure awareness (type tokens, factory patterns, array creation), generic inheritance...
Use when you need to review, improve, or refactor Java code for generics quality — including avoiding raw types, applying the PECS (Producer Extends Consumer Super) principle for wildcards, using bounded type parameters, designing effective generic methods, leveraging the diamond operator, understanding type erasure implications, handling generic inheritance correctly, preventing heap pollution with @SafeVarargs, and integrating generics with modern Java features like Records, sealed types, and pattern matching. Part of the skills-for-java project Source: jabrena/cursor-rules-java.