Robocode Online Web Application - what do You think?

Well, I'd agree that the algorithms etc needed to succeed in Robocode are more complex than just a language syntax. But I think a beginner or novice programmer has a pretty strong inclination towards certain languages, like the ones they already know (obviously) or that seem popular or easy to learn. In my mind, once you are starting to assess game rules and trying to design a good robot, you have already passed the "barrier to entry". :-) And I think that demographic is also more likely to play programming games than experienced software developers (though our numbers at the RoboWiki are surely skewed).

I do know that at several high schools in Seattle, Java is the language taught. Both AP and IB computer science courses use Java.