How many java supported platforms are there?

Question

I am designing a library that is going to use native code, but i plan on making it cross platform. I was wondering how many different versions i would have to write to support each native implementations such as windows, linux, mac osx.

Answer 1

Here is List of of operating system that Java 7 gives support to Oracle JDK 7 and JRE 7 Certified System Configurations