Amazon ElastiCache vs cache2k

Amazon ElastiCache is a managed caching service compatible with Valkey, Memcached, and Redis OSS, with performance described as microsecond latency. Customers can deploy a serverless cache or a node-based cluster. ElastiCache Serverless monitors compute, memory, and network use and scales vertically and horizontally as demand changes. It replicates data across multiple Availability Zones and offers a 99.99% availability SLA for each cache. Listed uses include application and semantic caching, data and session stores, and leaderboards. It can act as a front-end cache for Amazon RDS, Aurora, DocumentDB, and DynamoDB, and improve performance with EC2 and EMR. Security options include encryption in transit and at rest, IAM authentication, Valkey or Redis OSS AUTH, and role-based access control. CloudWatch provides more than 40 operational metrics at no additional charge. Valkey serverless pricing starts at $6 a month, billed according to stored data in GB-hours and requests measured in ECPUs. Data tiering is unavailable with ElastiCache Serverless.

cache2k is an Apache-licensed, open-source library that keeps Java application objects in memory. Its project describes a JAR smaller than 400 KB with no external dependencies, and the implementation is written in pure Java without sun.misc.Unsafe. Cache behavior includes automatic expiry, refresh, refresh ahead, read-through loading, and event listeners. Cache loaders can suppress exceptions or retry them according to configuration. Integrations listed include Spring Framework, Scala Cache, DataNucleus through JCache, and Hibernate through JCache. cache2k supports JCache / JSR 107, while its guide notes extra overhead for that API compared with the native interface. Monitoring options include low-overhead statistics, JMX, and documented Micrometer metrics. Version 2 requires Java 8 or later and is described as compatible with Android API level 26. The library is free, available from Maven Central, self-hosted, and does not persist data.