A few things:
If you HAD to run windows or linux, you could do it on your Mac. You could boot these natively on your Mac or run them in a virtualization program.
There's NO reason you can't program C or Java on your Mac. The only way that you'd have a problem is if there is a binary library you needed to use that was only available for another platform, but that is highly unlikely.
So now you need tools. What tools are your classmates using in Windows or Linux that you don't have available on OS X? Eclipse is the most common Java development environment and is available on all 3 platforms. The most popular C compilers are gcc, and now llvm is gaining some traction. These are available on any of these platforms. If you need an IDE for C, XCode can handle that for you without issue (I think Eclipse can to given the right components, plugins, what-have-you). So what do you *need* that's not available? What have you been told to use that you don't have a replacement for?
In short: OS X is a great development platform. It is a very "desktop-friendly" Unix with broad support for tons of languages.
-Lee