FullMoon.java

  LocalDateTime getNextFullMoon(LocalDateTime from);

  default List<LocalDateTime> getYearlyFullMoons(int year) {
    List<LocalDateTime> result = new ArrayList<>();
    LocalDateTime from = LocalDateTime.of(year , 1 , 1 , 0 , 0);

    while (from.getYear() < year+1) {
      LocalDateTime fullMoon = getNextFullMoon(from);
      if (fullMoon.getYear() == year)
        result.add(fullMoon);

      from = fullMoon.plusDays(1);
    }
    return result;
  }