Thanks for the reply: the good people of Stack Exchange fixed it (but then told me to delete the question as not being as good fit for the site....) In short: the way Timer.scheduledTimer is used has changed***. Someone supplied me with a different formula for using it, and that seems to have fixed it. I removed the sleep, and it seems to not be a problem without it. Anyway, the leak is fixed. *** What do you want to change things for? Things are bad enough as they are!