check-architecture

Run an architecture audit that checks layer boundaries, bean design, configuration, and transactions in phases. The review flags issues like controllers injecting repositories directly, services returning ResponseEntity, and stateful singletons, then outputs a severity-ranked report with fixes.

Trace injection chains between services to find cycles such as UserService injecting OrderService which injects UserService back. Spring Boot 3.x fails fast on circular references by default, so also check whether spring.main.allow-circular-references was set to true to work around a structural problem.

Deprecated methods like authorizeRequests() and antMatchers() may still compile in Boot 3.x but are incorrect. Migrate to authorizeHttpRequests() with requestMatchers(), and add @EnableMethodSecurity if @PreAuthorize annotations are used, since they are silently ignored without it.

Spring applies transactions through proxies, which cannot intercept private methods, so the annotation is silently ignored. Move the annotation to a public method or restructure the class so transactional boundaries sit on public entry points.

Synchronized methods and blocks pin virtual threads to carrier threads, destroying scalability under load. Replace synchronized with ConcurrentHashMap or ReentrantLock, and audit ThreadLocal usage since virtual threads do not inherit ThreadLocal context the same way.