The strength of the actor model is that actors are lightweight, which means you can use millions of them on a single JVM running on an ordinary computer. Most of the time, you are not going to use a single actor but many actors. This requires a model to handle multiple actors.
In Akka, actors are organized in hierarchical trees—meaning that every actor has a parent and can have multiple children. Next, we will have a look at a slightly more complicated example that will showcase how actors work in hierarchies.
