What is Spring Boot's caching abstraction and how do you use it?

// Enable caching:
@SpringBootApplication
@EnableCaching
public class App { ... }

// Service with caching:
@Service
public class ProductService {

    // Cache the result by productId:
    @Cacheable(value = "products", key = "#productId")
    public ProductDto findById(String productId) {
        return productRepo.findById(productId)  // only called on cache miss
            .map(this::toDto)
            .orElseThrow();
    }

    // Update the cache after saving:
    @CachePut(value = "products", key = "#result.id")
    public ProductDto save(Product product) {
        Product saved = productRepo.save(product);
        return toDto(saved);  // returns updated value AND updates cache
    }

    // Evict from cache on delete:
    @CacheEvict(value = "products", key = "#productId")
    public void delete(String productId) {
        productRepo.deleteById(productId);
    }

    // Evict all cache entries:
    @CacheEvict(value = "products", allEntries = true)
    public void clearAll() { }
}

# Configuring the cache provider in application.yml:
# Simple (in-memory, default when no other cache is configured):
spring:
  cache:
    type: simple

# Redis cache:
spring:
  cache:
    type: redis
    redis:
      time-to-live: 600s
  data:
    redis:
      host: localhost
      port: 6379

# Caffeine (high-performance in-memory):
spring:
  cache:
    type: caffeine
    caffeine:
      spec: maximumSize=1000,expireAfterWrite=300s