Considering the last year I'm pretty sure they don't even care if it works... or even if it's a game.

Yes, steam only care you pay the greenlight fee and that you get some votes...

I'm currently developing a 2D game in Java using LibGDX framework and I had no huge problems I couldn't solve so far. The problem of requiring the user to have Java installed on their computer can be solved by bundling the JRE in your own game (Launch4J + OpenJDK).

As for Steam, they accept any game that runs by executing a single file, so you should be fine.

As the other posters have said, as long as the runtime is bundled with the game Steam won't care that it is Java. There are quite a few Adobe AIR games on Steam now because you can bundle the AIR runtime in a nice package with a exe to run. Adobe is even worse then Java when it comes to being updated and security problems.

Probably my bad but I don't recall even a single game asking me or being bundled with any Java runtime (therefore written in Java)

Probably my bad but I don't recall even a single game asking me or being bundled with any Java runtime (therefore written in Java)

Standalone JRE requirement is usually on the part of miscellaneous utility programs. I got tired of fighting with JRE a long time ago and decided 'nevar again'. I have no issue with games that bundle their own runtime though. My favorite roguelike is Pixel Dungeon, which is bundled (originally Android).

The single biggest problem you're going to have with Java is version-of-the-week hell. Write once run anywhere is a joke.

Have you had an issue where desktop Java applications broken inbetween releases of the same Java version? (ie, from Java 7 u60 to Java u72 or something). Otherwise its an unfounded myth.

I've run my projects in more VM versions of OpenJDK and OracleJDK that I can count, played Minecraft with all the damn updates that came every two weeks or so, never had an actual VM compatibility problem. They do take retro compatibility very seriously (to a fault even), thus why no API was ever actually removed from the runtime.

Hell I've never in years had an issue where Eclipse would crash because some VM was incompatible, and Eclipse its a massive application.

And please, don't even mention applets. They shouldn't exist, its a Good Thing™ most of them stopped to work.

In any case, there wouldn't be any single damn problem if you just provided a link to download the JRE but Oracle is composed top to bottom from a pile of steaming stinky assholes and they bundle crapware with their damn JRE distributions (luckily they dont do it with the JDK). So yeah, bundle a JRE (20Mb to 40Mb, libGDX guys provide a tool to reduce the size of the VM by removing unwanted crap).

Still this is an issue that you will have in some measure whatever you choose. C# needs the .NET runtime (or Mono depending on the platform, which is a whole other issue altogether), Java needs the JRE, C++ will need whatever MSVC runtime you're using (or some specific glibc version depending on the platform), etc.

The answer to all of those is: Ship the dependencies with your application, and save yourself a headache.

The answer to all of those is: Ship the dependencies with your application, and save yourself a headache.

QFE. Sadly, this *still* isn't entirely common in the Windows world, and even native programs often require you to hunt down the correct MSVC redistributable...

@OP: Java is no more or less capable of 2D gamedev than any other language. There are however generally fewer resources around java game development than other toolkits (such as Unity's 2D support), but regardless, if you know Java already, it's often best to stick with what you know.