Akka is a concurrent, distributed, and fault-tolerant framework and runtime environment developed by Lightbend (formerly Typesafe). It supports the actor model initially developed in Erlang. So, Akka is greatly inspired by Erlang's actor.
The following image shows collaborating tasks by sending messages among actors. Actors send messages via mail boxes. Receiving actors check their mail boxes and process them. Actors can organize hierarchies. Parent actors can request their subtasks to child actors:
Akka itself is developed in Scala but it supports Java. We will use Okku, a Clojure wrapper for Akka.