Hazelcast allows us to be a first-hand witness to a lot of internal state information. By registering the listeners so that they can be notified as the events occur, we can further enhance an application not only in terms of its functionality, but also with respect to its resilience. By allowing the application to know when and what events are unfolding underneath it, we can add defensiveness to it, embracing the dynamic and destroyable nature of the ephemeral approaches towards applications and infrastructure.

In the next chapter, we will move away from data a little and look at the distributed execution and task processing capabilities that are being offered by Hazelcast.