Buying developers via github seemed focused toward JS. I went to [0] to prove it but turns out Java is the second most popular language on GitHub projects
Microsoft didn't donate "huge money" to Github, they bought the company outright...and that has nothing at all to do with Java despite the ill fitting observation that Github is "a DVCS tool that hosts a variety of Apache and other open source Java projects".
Also that's not what the article is about, it's about Microsoft increasing its investment in the Java Enterprise space, whilst their old "enemy" seem to be less interested.
And finally, Slashdot from 1998 called and asked for its "M$" back ;)
[0] https://octoverse.github.com/projects