This chapter covered Apache Ignite data grid concepts. It started with the JSR 107 specification, and covered cache configuration, cache events, listeners, and filters. We explored how the Hibernate L2 cache can be stored in Apache Ignite to improve application performance. 

Web session clustering is used to store user sessions in Apache Ignite Cluster to improve system availability, scalability, and performance. This chapter explored web session clustering with Apache Ignite.

In Chapter 4, Exploring the Compute Grid and Query API, we'll learn about the Apache Ignite compute grid, parallel processing, and the Query API.