[strictfp]

I would love process isolation on the JVM (several smaller heaps), and I'm not even into the actor model.

Plus I can imagine accidental mutability really being a problem. In my Akka course much effort was spent on explaining how to avoid side effect of it (no pun intended).

[ssmoot]

I guess the accidental mutability is a good point. Working in Scala, I've never encountered that.

You do learn not to close over local scopes in futures pretty quickly though.