As a user but nonprogrammer of java I have never found java to be cross-platform. It seems every application of any real complexity has required me to go on an hour long hunt for the right version and dependencies. If it take me longer to make your "cross-platform" application cross-platform than it does to install an OS, then there is a problem. These days if I get a whiff that a project is java based I avoid it and keep looking for another solution.