@NonNull
    private Date parseDate() {
        try {
            final Calendar cal = Calendar.getInstance();
            cal.setTimeInMillis(hiddenDate.getTime());
            cal.set(Calendar.HOUR_OF_DAY, 0);
            cal.set(Calendar.MINUTE, 0);
            cal.set(Calendar.SECOND, 0);

            return cal.getTime();
        } catch (final NumberFormatException e) {
            // cannot happen normally, but static code analysis does not know
            throw new IllegalStateException("hidden date must be a valid date for cache calendar entries");
        }
    }
@return {@code Date} based on hidden date. Time is set to 00:00:00.
main/src/main/java/cgeo/geocaching/calendar/CalendarEntry.java