There are projects that do something along the line of both of your suggestions. For iOS, there's a project called RoboVM. (it's still claimed to be alpha, but

There are projects that do something along the line of both of your suggestions. For iOS, there's a project called RoboVM. (it's still claimed to be alpha, but the game engine LibGDX uses it to deploy to iOS). For web, there's GWT, which allows you to develop web apps in Java and it compiles to HTML/CSS/JS (or something along that line, though I hear it's verbose. LibGDX/PlayN use it to deploy to the browser though)