code: private void readWorkWeeks(Project.Calendars.Calendar xmlCalendar, ProjectCalendar mpxjCalendar)
     {
        WorkWeeks ww = xmlCalendar.getWorkWeeks();
        if (ww != null)
        {
           for (WorkWeek xmlWeek : ww.getWorkWeek())
           {
              ProjectCalendarWeek week = mpxjCalendar.addWorkWeek();
              week.setName(xmlWeek.getName());
              Date startTime = xmlWeek.getTimePeriod().getFromDate();
              Date endTime = xmlWeek.getTimePeriod().getToDate();
              week.setDateRange(new DateRange(startTime, endTime));
  
              WeekDays xmlWeekDays = xmlWeek.getWeekDays();
              if (xmlWeekDays != null)
              {
                 for (WeekDay xmlWeekDay : xmlWeekDays.getWeekDay())
                 {
                    int dayNumber = xmlWeekDay.getDayType().intValue();
                    Day day = Day.getInstance(dayNumber);
                    week.setWorkingDay(day, BooleanHelper.getBoolean(xmlWeekDay.isDayWorking()));
                    ProjectCalendarHours hours = week.addCalendarHours(day);
  
                    Project.Calendars.Calendar.WorkWeeks.WorkWeek.WeekDays.WeekDay.WorkingTimes times = xmlWeekDay.getWorkingTimes();
                    if (times != null)
                    {
                       for (Project.Calendars.Calendar.WorkWeeks.WorkWeek.WeekDays.WeekDay.WorkingTimes.WorkingTime period : times.getWorkingTime())
                       {
                          startTime = period.getFromTime();
                          endTime = period.getToTime();
  
                          if (startTime != null && endTime != null)
                          {
                             if (startTime.getTime() >= endTime.getTime())
                             {
                                endTime = DateHelper.addDays(endTime, 1);
                             }
  
                             hours.addRange(new DateRange(startTime, endTime));
                          }
                       }
                    }
                 }
              }
           }
        }
     }
docs: Read the work weeks associated with this calendar.
  
  @param xmlCalendar XML calendar object
  @param mpxjCalendar MPXJ calendar object