I noticed using a memory profiling feature of the  VisualVM that
akka.Actor creates always two java.lang.reflect.Field objects for each
LocalActorRef that it keeps internally for each actor. See
http://github.com/jboner/akka/blob/master/akka-actor/src/main/scala/actor/ActorRef.scala 
for more info.

These objects dominate a memory consumption in the Ring benchmark for
rings with many e.g. 100000 elements. But this is just an example. Any
application that starts a lot of actors of the same class would expose
the same effect.

I'd say that since these two Field objects are immutable and depend
only on the class of the actor, but not on the specific instance, they
can be cached and shared between all Actors of the same class. This
would save memory and also eventually improve performance as the
number of reflection API calls can be reduced.