code: public NumberExpression<Integer> dayOfYear() {
          if (dayOfYear == null) {
              dayOfYear = Expressions.numberOperation(Integer.class, Ops.DateTimeOps.DAY_OF_YEAR, mixin);
          }
          return dayOfYear;
      }
docs: Create a day of year expression (range 1-356)
  <p>NOT supported in JDOQL and not in Derby</p>
  
  @return day of year