Hazelcast achieves distributed caching through its in-memory data grid (IMDG) architecture, which is designed to store and manage cached data across a cluster of multiple nodes. Here's how Hazelcast accomplishes distributed caching:

Partitioning : Hazelcast divides the cached data into partitions and distributes these partitions across the nodes in the cluster. Each node is responsible for storing and managing a subset of the data partitions. Partitioning allows data to be distributed evenly across the cluster, ensuring load balancing and scalability.

Replication : Hazelcast provides built-in support for data replication to ensure high availability and fault tolerance. Each partition is replicated to one or more backup nodes in the cluster, depending on the configured replication factor. If a node fails or becomes unreachable, the data stored on that node's partitions can be seamlessly retrieved from the backup nodes, maintaining data consistency and availability.

Client-Server Architecture : Hazelcast follows a client-server architecture, where client applications interact with the Hazelcast cluster through client nodes. Client nodes are lightweight instances that connect to the cluster and provide APIs for caching and retrieving data. Client nodes handle tasks such as data distribution, load balancing, and failover transparently to the client applications.
Consistent Hashing : Hazelcast uses consistent hashing to determine the mapping of data to partitions and nodes in the cluster. Consistent hashing ensures that the distribution of data remains stable even when nodes are added or removed from the cluster. This allows Hazelcast to efficiently route requests to the appropriate nodes without requiring a centralized lookup mechanism.

Automatic Data Rebalancing : When nodes are added or removed from the cluster, Hazelcast automatically rebalances the data partitions to ensure that each node maintains an approximately equal share of the cached data. This dynamic data rebalancing process helps maintain optimal performance and resource utilization across the cluster.

Cluster Membership Management : Hazelcast includes mechanisms for cluster membership management, node discovery, and communication. Nodes in the cluster communicate with each other to share information about the cluster topology, membership changes, and data distribution. This enables Hazelcast to adapt to changes in the cluster environment and ensure seamless operation in dynamic and distributed environments.