If you like to develop iOS applications in Java you should take a look at RoboVM. The RoboVM compiler translates Java bytecode into native ARM code that runs directly on the CPU. The compile time tools are licensed under the GPLv2.
Update Apr/2016: RoboVM has discontinued its development. See the libGDX main developer’s blog post for more information about the background and viable alternatives: http://www.badlogicgames.com/wordpress/?p=3925 (it’s Multi-OS engine)