Java is absolutely an option. There are loads of great titles out there written with it- Ever heard of MineCraft?
That said, coming off of 5 years playing around in XNA, I can say that the library and tooling (Visual Studio, XNA's Content Pipeline) are just fantastic and since Java and C# are very similar the learning curve would not be drastic. If I wasn't concerned about portability (XNA is stuck to Windows, 360, and Windows Phone) I'd be using it for my current project.
I'm presently working in C++ but it's hard for me to recommend that to fans of C# or Java. My suggestion though, is stick with what you know and love. There's no reason to not use Java if you're already very comfortable with it. You can get to OpenGL from Java using libraries like LWJGL, so there's no reason to dive into another language for it.