Distributed Cache with Embedded Infinispan

What You Will Learn

How to create a clustered Infinispan cache manager in embedded mode, configure a distributed (partitioned) cache, and observe how data is distributed across cluster nodes.

Prerequisites

Java 17+

Step 1: Add the Embedded Dependency

Add Infinispan core to your pom.xml:

<dependency>
   <groupId>org.infinispan</groupId>
   <artifactId>infinispan-core</artifactId>
</dependency>

Step 2: Create a Clustered Cache Manager

Use GlobalConfigurationBuilder.defaultClusteredBuilder() to enable JGroups clustering:

   public void createDefaultCacheManager() {
      // Setup up a clustered cache manager
      GlobalConfigurationBuilder global = GlobalConfigurationBuilder.defaultClusteredBuilder();
      // Initialize the cache manager
      cm1 = new DefaultCacheManager(global.build());
   }

This starts a JGroups cluster. Multiple instances on the same network will auto-discover each other.

Step 3: Configure a Distributed Cache

Create a cache with DIST_SYNC mode. In this mode, data is partitioned: each entry is stored on a subset of nodes (by default 2 copies):

   public void createAndPopulateTheCache(int size) {
      //Create cache configuration
      ConfigurationBuilder builder = new ConfigurationBuilder();
      builder.clustering().cacheMode(CacheMode.DIST_SYNC);
      // Create a cache
      cache = cm1.administration().withFlags(CacheContainerAdmin.AdminFlag.VOLATILE)
              .getOrCreateCache(DIST_CACHE_NAME, builder.build());
      // Store the current node address in some random keys
      for (int i = 0; i < size; i++) {
         cache.put(UUID.randomUUID().toString(), cm1.getNodeAddress());
      }
   }

Step 4: Populate and Query the Cache

Store entries and observe ownership. Use Flag.CACHE_MODE_LOCAL to see only entries owned by the local node:

   public void displayCacheContent() {
      if (cache == null) {
         System.out.println("The cache is null");
         return;
      }

      // Display the current cache contents for the whole cluster
      cache.entrySet().forEach(entry -> System.out.printf("%s = %s\n", entry.getKey(), entry.getValue()));
      // Display the current cache contents for this node
      // Note: By default numOwners=2, so in a cluster with 2 nodes, each node owns all the keys:
      // some of the keys as "primary owner" and some keys as "backup owner"
      cache.getAdvancedCache().withFlags(Flag.CACHE_MODE_LOCAL).entrySet()
              .forEach(entry -> System.out.printf("%s = %s\n", entry.getKey(), entry.getValue()));
   }

Step 5: Run the Tutorial

mvn package exec:java

The local view will show fewer entries than the cluster-wide view because distributed mode partitions data across nodes.

What’s Next

Try replicated mode where every node has all data
Add cache listeners to react to changes
Use distributed streams for parallel processing