cache2k – High Performance Java Caching

cache2k focuses on providing a well engineered in-memory object cache implementation for Java applications.

Maven Central

  Cache<String,String> cache = new Cache2kBuilder<String, String>() {}
    .expireAfterWrite(5, TimeUnit.MINUTES)    // expire/refresh after 5 minutes
    .resilienceDuration(30, TimeUnit.SECONDS) // cope with at most 30 seconds
                                              // outage before propagating 
                                              // exceptions
    .refreshAhead(true)                       // keep fresh when expiring
    .loader(this::expensiveOperation)         // auto populating function
    .build();

For a detailed introduction continue with Getting Started.

Features at a glance

Small jar file (less than 400k) with no external dependencies
Even smaller, for use with Android
Fastest access times, due to non blocking and wait free access of cached values, Blog article
Java 6 and Android compatible
Leverages Java 8 to increase performance (if possible)
Pure Java code, no use of sun.misc.Unsafe
Thread safe, with a complete set of atomic operations
Resilience and smart exception handling
Null value support, see User Guide - Null Values
Automatic Expiry and Refresh: duration or point in time, variable expiry per entry, delta calculations
CacheLoader with blocking read through, see User Guide - Loading and Read Through
CacheWriter
Event listeners
Refresh ahead reduces latency
Low Overhead Statistics and JMX support
Separate API with stable and concise interface
complete JCache / JSR107 support, complatible to JCache Specification 1.1
XML based configuration, to separate cache tuning from logic

Integrations

Spring Framework
Scala Cache
Datanucleus (via JCache)
Hibernate (via JCache)
…. and probably more, please raise an issue and get it listed!

News

Version 1.2.3.Final, 2019-08-08: Service release for stable version, See Version 1.2.3.Final release notes
Version 1.2.2.Final, 2019-06-06: Service release for stable version, See Version 1.2.2.Final release notes
Version 1.2.1.Final, 2019-03-08: Service release for stable version, See Version 1.2.1.Final release notes
Version 1.2.0.Final, 2018-08-23: Release of new stable version, See Version 1.2.0.Final release notes
Version 1.1.4.Beta, 2018-08-14: Preview. XSD Schema improvements, first release candidate for 1.2, See Version 1.1.4.Beta release notes
Version 1.1.3.Alpha, 2018-08-02: Preview. Configuration infrastructure improvements, XSD Schema, See Version 1.1.3.Alpha release notes
Version 1.1.2.Alpha, 2018-07-17: Preview. Spring integration, JCache cache creation, IntCache optimization, See Version 1.1.2.Alpha release notes
Version 1.1.1.Alpha, 2018-07-02: Preview. new jar file structure, See Version 1.1.1.Alpha release notes
Version 1.0.2.Final, 2017-12-29: Support JCache standard 1.1, See Version 1.0.2.Final release notes
Version 1.0.1.Final, 2017-08-14: minor bugfix release, See Version 1.0.1.Final release notes
Version 1.0.0.Final, 2017-07-11: Minor documentation tweaks, allow more chars in a cache name, See Version 1.0.0.Final release notes

Feedback

Please use the GitHub issue tracker for bugs and wishes you step upon. We also monitor the stackoverflow.com tag cache2k for general usage questions.

License

The code is released under Apache license.

Alternatives

cache2k does not try to be a full blown distributed enterprise caching solution. Some alternatives which you should take a look on:

Google Guava Cache
EHCache
JCS
Caffeine

Distributed caches:

Infinispan
hazelcast
redsisson
Apache ignite

Credits

Andrius Velykis for his maven reflow theme
Maximilian Richt for customizing the reflow theme and polishing the cache2k.org site design
Dr. Song Jiang for support, Hompage of Dr. Song Jiang