If the Logging is initialized after 12 P.M. the PeriodicRotatingFileHandler does not roll the file on midnight if the suffix '.yyyy-MM-dd' or Period=DAY is being used.

The culprit for this cause is in my unterstanding the usage of Calendar.clear(..) for the 'HOUR_OF_DAY' Field. As stated in http://download.oracle.com/javase/6/docs/api/java/util/Calendar.html#clear(int) the HOUR value will not be cleared in this case.

Probably the HALF_DAY Period setting has the same problem.