GoTo surfing.

Actually 64-bit would probably be worse in some things too. Specifically, 64-bit mode means pointers take twice as much memory, thus effectively doubling memory bandwidth requirements for code that spends most of it's cpu time dealing with pointers between objects. For the case of robocode bots, deep recursive data structures are not too uncommon, and additionally Java is more subject to this problem than compiled object oriented languages, because Java doesn't allow non-reference composition of classes.