a class variable having the same type of Class itself

Today I saw a class similar to this at my work place:

public class A {
    private Map<String, A> myMap = Maps.newHashMap();
}

The code compiles, works and does what it suppose to do. But it can be refactored to different design. But I don't understand why this design was chosen.

You can do silly things like this:

this.myMap.get("x").myMap.get("x").myMap.get("x");

My question:

Is there a really a good situation where we need to apply such design? Why?