Nor would you use it to design the next Microsoft Word, web browser, paint program or multimedia application. The tools aren't there. They don't need to be. If you're into Internet content delivery, Java is really big right now, but it's not the only game in town. More popular still is the freeware Perl programming language, whose syntax is derived from unix and C, and which comes in compiled and script flavors.
Perl hackers are everywhere on the web.
You can do anything in C or Perl that you can do in Java. You don't need to know the intricacies of the Mac Toolbox and the Microsoft Class Libraries to write code that can run on any platform. That's the problem for the people who write the API's. This is roughly where Microsoft comes in. The API concept is neither new nor patentable.