What data caching methods have you applied in your projects?

In Java projects, the following data caching methods were used:

• Built-in cache in applications: using collections like HashMap or ConcurrentHashMap to store frequently requested data in memory.

• Caching with libraries: for example, using Ehcache, Caffeine, or Guava Cache, which provide advanced features for cache lifetime management, maximum size, and eviction policies.

• Database-level caching: using built-in caching mechanisms or external solutions such as Redis or Memcached to store query results or sessions.

• Spring Cache: if the project uses Spring Framework, the Spring Cache module was used with annotations @Cacheable, @CachePut, and @CacheEvict for transparent method caching.

Example of using Caffeine Cache:

import com.github.benmanes.caffeine.cache.Cache;
import com.github.benmanes.caffeine.cache.Caffeine;

Cache<String, String> cache = Caffeine.newBuilder()
    .maximumSize(1000)
    .expireAfterWrite(10, java.util.concurrent.TimeUnit.MINUTES)
    .build();

// Adding to cache
cache.put("key1", "value1");

// Retrieving from cache
String value = cache.getIfPresent("key1");