code: public static Date getFirstDayFromCurrentWeek(Date d) {
          Calendar cal = Calendar.getInstance();
          cal.setTime(d);        
          cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
          cal.set(Calendar.HOUR_OF_DAY, 0);
          cal.set(Calendar.MINUTE, 0);
          cal.set(Calendar.SECOND, 0);
          cal.set(Calendar.MILLISECOND, 0);
          return cal.getTime();
      }
docs: Get first date from current week
  @param d date
  @return first date from current week