code: private static Set<Date> getHolidaySet(int year) {
  		if (holidays == null) {
  			holidays = new HashMap<Integer, Set<Date>>();
  		}
  		if (!holidays.containsKey(year)) {
  			Set<Date> yearSet = new HashSet<Date>();
  
  			// Add set holidays.
  			yearSet.add(getDate(1, Calendar.JANUARY, year));
  			yearSet.add(getDate(1, Calendar.MAY, year));
  			yearSet.add(getDate(17, Calendar.MAY, year));
  			yearSet.add(getDate(25, Calendar.DECEMBER, year));
  			yearSet.add(getDate(26, Calendar.DECEMBER, year));
  
  			// Add movable holidays - based on easter day.
  			Calendar easterDay = dateToCalendar(getEasterDay(year));
  
  			// Sunday before easter.
  			yearSet.add(rollGetDate(easterDay, -7));
  
  			// Thurday before easter.
  			yearSet.add(rollGetDate(easterDay, -3));
  
  			// Friday before easter.
  			yearSet.add(rollGetDate(easterDay, -2));
  
  			// Easter day.
  			yearSet.add(easterDay.getTime());
  
  			// Second easter day.
  			yearSet.add(rollGetDate(easterDay, 1));
  
  			// "Kristi himmelfart" day.
  			yearSet.add(rollGetDate(easterDay, 39));
  
  			// "Pinse" day.
  			yearSet.add(rollGetDate(easterDay, 49));
  
  			// Second "Pinse" day.
  			yearSet.add(rollGetDate(easterDay, 50));
  
  			holidays.put(year, yearSet);
  		}
  		return holidays.get(year);
  	}
docs: Get a set of holidays for a given year.
  
  @param year
  The year to get holidays for.
  @return The set of dates.