Added a few reports to maven, one of 'm is checkstyle. This reports checks the style of your source code and sees if it is conform specific standards. My source code didn't :-) Horrified I saw my code generated 2448 style errors. Most of them were missing javadoc comments and tabs instead of spaces. Also more serious ones like catching unspecified exceptions and having a to high Cyclomatic Complexity (8).
So I sat down behind laptop this weekend and forced myself through 2448 errors and solved every single one of them in two days time :-) Lesson learned: Write clean code ;-)