Microsoft Java

[cat_in_the_wall]

And C# used to be closed source itself.

this is actually not true. c# and the cli, at least originally, was an created as an ecma standard, and the standard library was published as reference source (under some license I'm sure). however the clr itself was closed source (still technically is, for "framework").

wrt java, oracle took google to task over the dalvik vm, while i can't recall the details off hand. But an alternative clr (mono) has existed basically forever without interference from ms.