[pjmlp]

Microsoft is hardly much different, and contrary to Sun/Oracle once upon a time the gatekeeped .NET features behind different support levels on Visual Studio, like contracts, nowadays gone because obviously the adoption wasn't that great.

There are also some tooling features like code coverage, live testing or byte code rewriting tooling that require Visual Studio Enterprise licenses.

IKVM and J# were two ways of running Java code on .NET.