public static LocalDate getLocalDate(long epochMillis) {
        long localEpochDay = Math.floorDiv(epochMillis, MILLIS_PER_DAY);
        return LocalDate.ofEpochDay(localEpochDay);
    }
The number of days from year zero to year 1970.
There are five 400 year cycles from year zero to 2000.
There are 7 leap years from 1970 to 2000.
indexr-common/src/main/java/io/indexr/util/DateTimeUtil.java