This chapter was all about the world of clustered applications. Here, we took you through the robust clustering features of WildFly and applied them to some of the examples discussed in this book.

The number of topics related to clustering might be expanded to cover a full book of its own; however, we decided to stress only on some features. In particular, we learned how to cluster EJBs and achieve fault tolerance in case there is a change in the server topology.

Next, we discussed clustering web applications and the integration with load balancing solutions such as the Apache web server and mod_cluster.

In the next chapter, we will focus on some new topics added to Java EE 7 related to long-term task execution: batch processing and concurrency utilities' usage.