cache2k is a high performance and light weight in-process caching library. Compared to other libraries (EHCache, Guava and Caffeine) it achieves the highest throughput for cache hits while still providing one of the best eviction efficiency. Advanced features of cache2k, like refresh ahead and resilience can solve typical application problems with ease.

This change log lists the complete changes since the last stable version 1.4.1.Final.

New and Noteworthy

  • New timer based on hierarchical timer wheels, which is more performance and scales linear with more cache entries
  • No more extra thread per cache, in cache timer is used, e.g. for expiry

Potential breakages

  • No separate executor for async listeners by default any more. If an async listener executor is not specified it uses the executor defined by Cache2kBuilder.executor which in turn defaults to the common ForkJoinPool in Java 8.
  • Slightly more lag for operations triggered by time, e.g. cache cleanup after expiry, calls of expiry listeners, refreshing. The lag can be controlled by Cache2kBuilder.timerLag

API Changes

  • Deprecated ExpiryTimeValues.NO_CACHE
  • Deprecated Cache2kBuilder.prefetchExecutor, introduced Cache2kBuilder.refreshExecutor (rename)
  • Deprecated Cache.prefetch and Cache.prefetchAll

Fixes and Improvements

  • Remove hash quality metric
  • MutableCacheEntry.reload() does load the entry even if already cached
  • After recovering from a load exception the expiry policy did not see the correct previous entry value with the exception
  • Improved internal structure and test coverage

Using this cache2k version

The binaries are available on maven central.

For Java SE/EE and Android environments

For Maven users:

    <dependency>
      <groupId>org.cache2k</groupId>
      <artifactId>cache2k-base-pom</artifactId>
      <version>1.6.0.Final</version>
      <type>pom</type>
    </dependency>

Recommended for Gradle users:

def cache2kVersion = '1.6.0.Final'

dependencies {
    implementation "org.cache2k:cache2k-api:${cache2kVersion}"
    runtimeOnly "org.cache2k:cache2k-core:${cache2kVersion}"
}

Note to Android users: The included jar files contain code that might only be needed in server environments (e.g. JMX support). It is possible to strip unnecessary code. Example ProGuard rules can be found at Andriod - cache2k User Guide

Using the JCache / JSR107 provider

Maven users include the cache2k JCache provider this way:

    <dependency>
      <groupId>org.cache2k</groupId>
      <artifactId>cache2k-jcache</artifactId>
      <version>1.6.0.Final</version>
      <scope>runtime</scope>
    </dependency>

For Gradle users:

dependencies {
    runtimeOnly "org.cache2k:cache2k-jcache:1.6.0.Final"
}

Implementation details, tuning tips and hints on configuration can be found at: [JCache - cache2k User Guide](https://cache2k.org/docs/latest/user-guide.html#jcache

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Version: 1.6.0.Final. Last Published: 2020-10-09.