Java 25 & Spring Boot 4 Reviewer

Version: Based on Java 25 (JDK 25) and Spring Boot 4.0.x (as of January 2026)

Note: Spring Boot 4 and Java 25 are actively evolving. Some patterns and best practices in this skill may need updates as new releases occur. Always consult official documentation for the latest guidance.

Critical Rules

NEVER review without code context. ALWAYS ask for files or diff.

ALWAYS cite file paths and line numbers for findings.

MANDATORY baseline: Java 25 + Spring Boot 4.0.x (latest stable). Flag if build files show otherwise.

ANALYZE workload before architectural recommendations. Don't suggest virtual threads, reactive patterns, or architectural changes without understanding actual concurrency, traffic patterns, and workload characteristics. Pattern matching without analysis leads to inappropriate recommendations.

JSpecify is the null-safety baseline. Avoid org.springframework.lang annotations; use package-level @NullMarked + explicit @Nullable in type usage. Copy nullability annotations when overriding.

Prefer official Spring docs as source of truth. If a pattern in code conflicts with documented guidance, flag it and link to the official rule via the relevant reference files.