To answer some of your questions (I use vertx and mainly focus on the JVM world) - reactive is actually a widely used term in the java world to mean "event loop

To answer some of your questions (I use vertx and mainly focus on the JVM world) - reactive is actually a widely used term in the java world to mean "event loop with async programming. Origin of the term here: https://www.reactivemanifesto.org/ https://www.reactivemanifesto.org/ Graal is an R&D effort by a few folks in the java community driven by oracle right now to allow AOT compilation among other things for the JVM: http://www.oracle.com/technetwork/java/jvmls2015-wimmer-2637907.pdf http://www.oracle.com/technetwork/java/jvmls2015-wimmer-2637... Java is generally not for apps that require fast VM spin up times. That being said, for what the JVM ecosystem can do it isn't bad in practice for heavy server applications. I know gravitational mainly works in the go ecosystem which has its own trade offs there, but considering what else java already has a mature ecosystem for (big data, well understood native internals, other language built on top of it) the startup times and weaknesses while not ideal haven't been a show stopper. GraalVM is an attempt to address a wide variety of problems you get with JVM startup time, GC etc. At most it's simplistic right now and will be for a while. The fact they are working on it is really cool though! Hope that helps!