One explanation could be large open source organizations like Apache and eclipse mirroring their code more and more on github. And all the old codehaus stuff that's been moved. Just a guess...

Java's picking up steam again. 8 and 9 released recently, OpenJDK is every bit as good as Oracle JDK, it's as fast as C++ these days, I'd guess a lot of libraries and things being rewritten for a new generation - eliminating old cruft, and starting new projects in modern Java.

> it's as fast as C++ these days

And C++ is as safe as Java these days. [1]

I wonder which claim is more optimistic. :)

[1] shameless plug: https://github.com/duneroadrunner/SaferCPlusPlus

Do you know of a good resource to catch up on this "modern" Java for someone who dropped it in the early 00's?

http://clojure.org/ :)

There's a large uptick in everything.

It would be nice to see a log version of this graph (either with just the vertical axis logarithmic or both).

True. I was not comfortable with the linear version (especially with the 14 languages now). I will publish both.

C++/C# repositories have more or less doubled since Jan16 (from 10000ish to 20000ish) and so have Java ones (75000ish to 150000ish).

So, there is not really an uptick in terms of percentage, the rise is more apparent in Java (and Javascript) case since they were more popular in the first place.

To see the relative shift in popularity, you would have to normalize the data against the total repos, I think.

Also language popularity based on this data might not be a fair conclusion. Some languages and environments do not lend themselves to OSS. For example, how many iOS app developers (using Swift) open source their app? Another is how many C# devs are using github as their repository over the various MS technologies.

Of course, in the context of github.

Android maybe?

Also the success of Minecraft which was written in Java might be encouraging people to make their own game engines or open source their own Java mods, etc. Just an idea, not sure if it's true.