Let Genetic Algorithms (more specific: Genetic Programmic) do the work for you.
Here you will find more information about that and how to obtain the source code (of course you can try for yourself).
Another article covers some general overview of RobocodeJGAP (written in German).
Have fun creating robots in Java with RobocodeJGAP and Genetic Algorithms!
Try to go for the higher ranks on the Robocode website RoboRumble@Home or on the Robocode Repository!