what to do with about printing to much?
Unfortunately, RoboRunner seems to suffer from the same issue.
Set DISPLAY variable to something crazy and run RoboRunner you will see it crush as well.
Try adding the "-Djava.awt.headless=true" parameter to how you invoke Java. I believe that does the trick. I seem to recall once trying this in the past.
This helps with rumble clients, so it probably good idea to ping developers about this switch to be on by default.
However, it does not help with RoboRunner.
You can update the JVM arguments passed to the Robocode process by modifying "jvmArgs" in roborunner.properties. Each thread starts in its own process with its own JVM because the Robocode engine isn't thread-safe.
Edit: And I'll put it on my RoboRunner to-do list. :-) I didn't have any other plans for a next version but it could probably use a few touchups...