code: public static Date dateReservedYear999(Calendar calendar) {
          calendar.set(Calendar.MONTH, Calendar.DECEMBER);
          calendar.set(Calendar.DAY_OF_MONTH, 31);
  
          return dateReservedDay999(calendar);
      }
docs: 将一个日期的月,日,时,分,秒,毫秒调整为最大值
  
  @param calendar 一个日期
  @return 被转化后的日期
  @see #dateReservedYear999(Date)