I also work in .NET stack but until now(before .net core), the entire CLR was a blackbox and could only run on Windows.Obviously we had Rotor released but licen

I also work in .NET stack but until now(before .net core), the entire CLR was a blackbox and could only run on Windows.Obviously we had Rotor released but license was restrictive and there was Mono but in my experience mono was far from production ready when it came to asp.net. In terms of the IDEs like VS or IntelliJ or a supported production ready server (kestrel like) there was not much option. I think the place where java still shines is JVM.There are myriads of JVM implementations out there which is suited for all kinds of purposes.And with the same flexibility ,there are functional languages like Scala or Clojure which targets JVM where all existing java libraries can be used for your new shiny language of choice.Of course .NET has F# or DLR (which I feel is another layer added on top of CLR and I couldn't like it). What I see is .net has ports for most of the java frameworks or libraries e.g spring,hibernate,lucene,akka you name it. With .NET core being open and F# and C# being super awesome on it's territories (yes am biased :) ) ,we may have good contender to java in some more time.