Redis cache testing with a real Redis instance catches behaviors that embedded or mocked alternatives cannot: TTL expiry timing, cache eviction under memory pressure, cluster failover behavior, and the exact serialization format that Redis stores data in. This article covers testing Spring Cache, Spring Session, and distributed locks against a real Redis container. What You’ll Learn Redis GenericContainer setup and @ServiceConnection (Spring Boot 3.2+) Testing Spring Cache with @Cacheable, @CacheEvict, and @CachePut Verifying TTL expiry behavior Testing Spring Session with Redis Testing distributed locks with Redisson or Spring Integration Dependencies <dependency> <groupId>org.

How Spring Security Uses Sessions For form login and traditional web applications, Spring Security stores the Authentication object in the HTTP session. On every request, SecurityContextPersistenceFilter (Spring Security 5) or SecurityContextHolderFilter (Spring Security 6) loads the SecurityContext from the session and puts it in the SecurityContextHolder. For stateless APIs using JWT or OAuth2 Bearer tokens, no session is created — the token is verified on every request. Session Creation Policy Control when Spring Security creates sessions:

Caching sits between your application and the database. A cache hit returns data in microseconds; a database query takes milliseconds. For frequently-read, infrequently-changed data, caching is the highest-leverage performance improvement. Spring Cache Abstraction Spring’s cache abstraction lets you add caching with annotations — the backing store (Caffeine, Redis, Hazelcast) is swappable: @Service @RequiredArgsConstructor public class ProductService { private final ProductRepository repository; @Cacheable("products") // cache the result public Product findById(UUID id) { return repository.

Caching reduces database load and response latency. Spring Boot’s cache abstraction lets you add caching with annotations, then swap the implementation (Caffeine, Redis, multi-level) without changing your business code. This guide covers Caffeine for in-JVM caching, Redis for distributed caching, and a multi-level cache that combines both. Spring Cache Abstraction Spring’s cache abstraction uses three annotations: Annotation Behaviour @Cacheable Cache the return value. On subsequent calls, return from cache without executing the method.