Q1. How does caching work in Spring?
Spring provides a caching abstraction that allows you to add caching to methods without coupling to a specific cache implementation. Use annotations like @Cacheable, @CacheEvict, @CachePut. Enable caching with @EnableCaching. The actual cache store (e.g., ConcurrentHashMap, Ehcache, Redis) is pluggable.
Q2. What is @Cacheable?
@Cacheable indicates that the result of a method should be cached. When the method is called, Spring checks if the result is already in the cache; if so, it returns the cached value without executing the method. Parameters: value (cache name), key (SpEL expression), condition, unless.
Q3. What is @CacheEvict?
@CacheEvict is used to remove entries from the cache. It can be triggered before or after method execution (by default after). Use allEntries=true to clear the entire cache.
Q4. What is @CachePut?
@CachePut always executes the method and updates the cache with the result. It does not skip execution like @Cacheable. Useful for cache updates after a create/update operation.
Q5. How do you use Redis as a cache provider?
Add spring-boot-starter-data-redis dependency. Spring Boot auto-configures RedisCacheManager. Configure Redis connection properties. Then use caching annotations as usual.