Help saving data?

I don't know java files very well, and I want to have a bot record some data for research. Whenever I try to make a file to record stuff in, robocode stops the bot. I am trying to create a file in the robot's data directory, but I must be doing something wrong. How do you specify a path to a directory in which you are allowed to write?

You can use AdvancedRobot.getDataDirectory() to get the path you're allowed to write in. Alternatively, you can use AdavancedRobot.getDataFile(String filename)

To enforce the write quota, Robocode also requires that you write to the file using RobocodeFileOutputStream or RobocodeFileWriter (instead of FileOutputStream or OutputStreamWriter)

(and is mentioned on Saving Gun Data of course you can adjust the write quota)