Hazelcast IMDG is a distributed in-memory object store and compute engine that supports a wide variety of data structures such as Map, Set, List, MultiMap, RingBuffer, HyperLogLog.

Use Hazelcast IMDG to store your data in RAM, spread and replicate it across a cluster of machines, and perform data-local computation on it.

Hazelcast is:

• cloud and Kubernetes friendly
• often used as a Distributed Cache amongst other use cases

• The HazelcastInstance bean is initialized lazily by Quarkus, if you want eager initialization, make sure to double-check Quarkus Documentation.

You can add the hazelcast-client extension to your Quarkus project by adding the following dependency:

<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-hazelcast-client</artifactId>
</dependency>

The extension exposes a single native-mode-compatible Hazelcast Client bean (HazelcastInstance) which can be directly injected into your beans:

@Inject
HazelcastInstance hazelcastClient;

By default, client will try to connect to a Hazelcast instance running on the host using port 5701.

Defaults can be customized using application.properties entries such as:

quarkus.hazelcast-client.cluster-name
quarkus.hazelcast-client.cluster-members
quarkus.hazelcast-client.outbound-port-definitions
quarkus.hazelcast-client.outbound-ports
quarkus.hazelcast-client.labels
quarkus.hazelcast-client.connection-timeout

All of them mirror standard Hazelcast Client configuration options.

If you need more, use a standard hazelcast-client.yml/hazelcast-client.xml-based configuration (described below) or wire-up your own HazelcastInstance bean. Keep in mind that you will still be able to benefit from GraalVM compatibility!

In order to configure the client using the hazelcast-client.yml file, place the configuration file in the src/main/resources directory.

Configuration entries from hazelcast-client.yml override all quarkus.hazelcast-client.* entries.

To make testing simple, the extension provides the HazelcastServerTestResource which automatically launches an embedded Hazelcast instance with defaults settings and manages its lifecycle:

 @QuarkusTest
 @QuarkusTestResource(HazelcastServerTestResource.class)
 public class HazelcastAwareTest {

     @Test
     public void test() {
         // you can safely call embedded Hazelcast instance from here
     }
 }

<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-test-hazelcast</artifactId>
    <scope>test</scope>
</dependency>

• Default Java serialization is not supported
• User code deployment is not supported