JCache Overview

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Hazelcast offers a specification-compliant JCache implementation. To show our commitment to this important specification that the Java world was waiting for over a decade, we did not just provide a simple wrapper around our existing APIs; we implemented a caching structure from the ground up to optimize the behavior to the needs of JCache. The Hazelcast JCache implementation is 100% TCK (Technology Compatibility Kit) compliant and therefore passes all specification requirements.

In addition to the given specification, we added some features like asynchronous versions of almost all operations to give the user extra power.

This chapter gives a basic understanding of how to configure your application and how to setup Hazelcast to be your JCache provider. It also shows examples of basic JCache usage as well as the additionally offered features that are not part of JSR-107. To gain a full understanding of the JCache functionality and provided guarantees of different operations, read the specification document (which is also the main documentation for functionality) at the specification page of JSR-107.

Supported JCache Versions

The following versions of the JCache specification have been released:

  • The original release, version 1.0.0, was released in March 2014. Hazelcast versions 3.3.1 up to 3.9.2 (included) implement version 1.0.0 of the JCache specification.

  • A maintenance release, version 1.1.0 was released in December 2017. Hazelcast version 3.9.3 and higher implement JCache specification version 1.1.0.

  • A patch release, version 1.1.1 was released in May 2019. Hazelcast version 3.12.1 and higher implement JCache 1.1.1.

JCache 1.1.x versions are backwards compatible with JCache 1.0.0. As maintenance releases, JCache 1.1.x versions introduce clarifications and bug fixes in the specification, reference implementation and TCK, without introducing any additional features.

Upgrading from JCache 1.1.0 to 1.1.1

JCache 1.1.1 is a bug-fix-only release. There are no behavioral differences between the JCache 1.1.0 and 1.1.1 specifications.

Upgrading from JCache 1.0.0 to 1.1.0

When upgrading from a Hazelcast version which implements JCache 1.0.0 to a version that implements version 1.1.0 of the specification, some behavioral differences must be taken into account:

  • Invoking CacheManager.getCacheNames on a closed CacheManager returns an empty iterator under JCache 1.0.0. While under JCache 1.1.0, it throws IllegalStateException.

  • Runtime type checking is removed from CacheManager.getCache(String), so when using JCache 1.1.0 one may obtain a Cache by name even when its configured key/value types are not known.

  • Statistics effects of Cache.putIfAbsent on misses and hits are properly applied when using JCache 1.1.0, while under JCache 1.0.0 misses and hits were not updated.

Note that these behavioral differences apply on the Hazelcast member that executes the operation. Thus when performing a rolling member upgrade from a JCache 1.0.0-compliant Hazelcast version to a newer Hazelcast version that supports JCache 1.1.0, operations executed on the new members exhibit JCache 1.1.0 behavior while those executed on old members implement JCache 1.0.0 behavior.

The complete list of issues addressed in JCache specification version 1.1.0 is available on Github.

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