An application uses a cache instance to store, retrieve, and share data objects within WebSphere Application Server dynamic cache.
Each cache instance can be configured independently for Java Naming and Directory Interface (JNDI) name, cache size, priority, and disk offload. Objects stored in a particular cache instance are not affected by other cache instances. This means if you store an object named object_1 with a value of object_data in cache instance x, you can also store an object with the same name, but different value in cache instance y.
Objects stored in a particular cache instance are available to applications on other servers by accessing a cache instance of the same name. The two servers must be within the same replication domain to share data.
The programming interface to access a cache instance is DistributedMap. You can locate DistributedMap in the com.ibm.websphere.cache Java package. See the DistributedMap Javadoc for more information.