code: public final void showYear(Year year) {
          requireNonNull(year);
          if (!yearPage.isHidden()) {
              selectedPage.set(getYearPage());
              setDate(year.atDay(1));
          }
      }
docs: Sends the request to the calendar view to display the given year. The
  view will switch to the {@link YearPage} and set the value of
  {@link #dateProperty()} to the first day of the year.
  
  @param year the year to show in the view