At some stage one will have to deal with the concept of "working" or "business" days. With the calendar functionality in Java it is pretty straightforward to find out whether a day is a week day or a Saturday or Sunday.
What I am interested in is, if anybody has implemented a calendar utility that allows me to do:

MyCalendar today = MyCalendar.getInstance();
MyCalendar newDate = today.addWorkingDays(5);

and would take into account the public holidays. Even if your solution includes a database table that stores all the public holidays, i am interested to see how you have implemented it.