My mate and I are gonna make a game for Steam and I, as the programmer, want to use Java as that is my current favorite language. So I need to know, does Steam notify the user that they need Java for a game when they buy/download/install it?
To answer your question directly, no Steam doesn't notify the purchaser that the game needs Oracle's Java Runtime Environment installed to play the game. That's because there shouldn't be any need to, any game that has a dependency on the JRE will download and install it as part of the normal Steam installation procedure. This is no different than games that have dependencies on Microsoft's Visual Studio, DirectX or .NET runtime. There is even a standard JRE depot that you can use.
That said, I personally refuse to buy or install any game that dependent on Oracle's JRE. I don't want to have to deal with that nonsense. An alternative route would follow Minecraft's lead an include a Java VM as part of the game itself. That is, instead of installing a VM for all Java applications on the machine to use, like with the Oracle JRE, you install a VM side-by-side your game that only your game uses. I don't think you can do this with the Oracle JRE, I believe Minecraft uses one based on OpenJDK.
On the other hand, if you're just starting out, you should probably take the easy route and use the standard Oracle JRE install, and just accept some people won't like that.
This is by no means an answer, but some points to consider. It did not fit in the comments box.
I would think that even if you were to use c++, you would need to ship your game with a bunch of Redistributable, at least on Windows. Unless you can manage to not use Visual Studio tools and such. I don't know what happens for Mac users.
And if you go with Java, I believe there would be a way to ship the JVM with your game. This would increase the download size, but it would ensure
- that the client has a jvm, and
- that the client has the correct jvm version for your game
Note that it is already necessary to ship the JVM with the game if you are distributing through the Mac App Store, so if you plan on distributing beyond Steam, this may be necessary anyway.