Spring Boot Caching Strategies: Improving Performance with @Cacheable

In modern web applications, performance plays a pivotal role in user experience and scalability. One of the most effective yet often overlooked strategies for improving performance in Spring Boot applications is caching. By avoiding repeated computations and database hits for frequently accessed data, caching drastically reduces latency and load on the backend.

This blog explores how to implement caching in Spring Boot using the @Cacheable annotation, detailing how it works, best practices, and the available tools and configurations to make your application more responsive and efficient.

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Why Caching Matters

Applications often process repetitive read operations that do not change frequently—for example, user profile retrieval, category lists, or configuration settings. Without caching, each of these calls hits the database, consuming time and resources.

Caching helps in:

• Reducing database load
• Improving API response times
• Enhancing scalability under concurrent loads

Spring Boot makes caching seamless and extensible with minimal configuration, especially using annotations like @Cacheable.

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Getting Started with Spring Boot Caching

Spring Boot provides abstraction over various caching providers (EhCache, Redis, Caffeine, etc.) through the Spring Cache module.

To enable caching in a Spring Boot project:

javaCopyEdit@SpringBootApplication
@EnableCaching
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

The @EnableCaching annotation activates Spring’s annotation-driven cache management capability.

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Understanding @Cacheable

The @Cacheable annotation tells Spring to cache the result of a method execution and reuse it for subsequent calls with the same parameters.

Example:

javaCopyEdit@Cacheable("products")
public Product getProductById(Long id) {
    simulateSlowService();
    return productRepository.findById(id).orElse(null);
}

Behavior:

• On first call with a specific id, the method is executed and the result is cached.
• On subsequent calls with the same id, the cached result is returned.
• If the method is called with a different id, it’s executed again and the result is cached.

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Customizing Cache Keys

By default, Spring uses method parameters as the cache key. You can customize the cache key using the key attribute:

javaCopyEdit@Cacheable(value = "products", key = "#id")
public Product getProduct(Long id) {
    return productRepository.findById(id).orElse(null);
}

You can also use SpEL (Spring Expression Language) for more complex keys.

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Conditional Caching

Spring allows conditional caching using the condition and unless attributes.

javaCopyEdit@Cacheable(value = "products", unless = "#result == null")
public Product getProduct(Long id) {
    return productRepository.findById(id).orElse(null);
}

• condition evaluates before method execution.
• unless evaluates after method execution.

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Evicting Cache with @CacheEvict

Caching stale data can be harmful. Use @CacheEvict to remove outdated entries.

javaCopyEdit@CacheEvict(value = "products", key = "#id")
public void updateProduct(Long id, Product updatedProduct) {
    productRepository.save(updatedProduct);
}

You can also clear entire caches with:

javaCopyEdit@CacheEvict(value = "products", allEntries = true)
public void clearCache() {
    // clear all cached products
}

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Choosing a Cache Provider

Spring Boot supports multiple cache providers. Some common choices:

Cache Provider	Best For	Notes
ConcurrentMap	Development/testing	In-memory, default
EhCache	Small to medium applications	Disk and memory cache
Redis	Distributed systems, microservices	Scalable, fast, requires setup
Caffeine	High-performance in-memory cache	Advanced expiration and eviction

Spring Boot auto-configures supported providers via the spring.cache.type property.

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Spring Cache Configuration Example (Redis)

yamlCopyEditspring:
  cache:
    type: redis
  redis:
    host: localhost
    port: 6379

Add Redis dependency:

xmlCopyEdit<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

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Best Practices for Spring Caching

1. Use meaningful cache names: Helps in monitoring and troubleshooting.
2. Evict on updates: Keep cache in sync with the database.
3. Avoid caching nulls: Can be misleading and introduce bugs.
4. Use time-to-live (TTL) for dynamic data: Avoid stale reads.
5. Monitor cache hit/miss rates: Tune configuration based on real usage.

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Monitoring and Metrics

Spring Boot with Actuator provides cache statistics when enabled.

yamlCopyEditmanagement:
  endpoints:
    web:
      exposure:
        include: 'caches'

Access:
GET /actuator/caches

You can also integrate tools like Micrometer for deeper observability or use Redis’ built-in CLI for command-line monitoring.

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Conclusion

Caching in Spring Boot using @Cacheable is a powerful, declarative way to boost application performance with minimal code changes. When used wisely, it can significantly reduce load on downstream services and databases while improving responsiveness.

Spring’s flexible caching abstraction makes it easy to switch between providers without major code refactors. As your application scales, investing in the right caching strategy will pay off in speed and efficiency.

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