At work I had a bug assigned to me. I fixed the bug last week, and today was the first chance I got to test it in a realistic environment. Sadly I appear to have made the behavior worse than before. I did fix the bug, but introduced a new, and harder to find bug. It is extremely frustrating, because on visual inspection of the code everything looks correct. Obviously it is not.
My fear is that it is some subtle Java behavior I am unfamiliar with since Java is still a new language to me.