cache2k vs Hazelcast Platform

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.

Hazelcast Platform brings a distributed compute engine and an in-memory data store together for real-time and AI-driven applications. It can process streaming data before storage, supporting action on data in motion, and provides fast reads and writes for interactive request/response workloads. SQL processing, stateful processing, event-time windows, and Java and SQL are listed capabilities. WAN Replication synchronizes clusters and supports automatic failover to a secondary cluster for disaster recovery. Security features include JAAS role-based access controls and TLS encryption for data moving between nodes and applications. The platform runs on public and private clouds, is available through AWS, Google Cloud, and Azure marketplaces, and supports hybrid deployment. Its Kafka Connector processes Apache Kafka topic streams and sends processed data back to Kafka. Hazelcast identifies mission-critical, data-intensive AI workloads as a focus, including use in financial services, retail, supply chain, and healthcare. The platform is available for Linux, macOS, and Windows, as well as through an API and self-hosted deployment. A free plan and free 30-day Enterprise trial are listed; the trial requires a requested license key. The annual self-managed subscription includes professional support, with pricing available by request.