Localized definitions of the day-of-week, week-of-month and week-of-year fields. !(p) A standard week is seven days long, but cultures have different definitions for some other aspects of a week. This class represents the definition of the week, for the purpose of providing {@link TemporalField} instances. !(p) WeekFields provides five fields, {@link #dayOfWeek()}, {@link #_weekOfMonth()}, {@link #weekOfYear()}, {@link #_weekOfWeekBasedYear()}, and {@link #_weekBasedYear()} that provide access to the values from any {@linkplain Temporal temporal object}. !(p) The computations for day-of-week, week-of-month, and week-of-year are based on the {@linkplain ChronoField#YEAR proleptic-year}, {@linkplain ChronoField#MONTH_OF_YEAR month-of-year}, {@linkplain ChronoField#DAY_OF_MONTH day-of-month}, and {@linkplain ChronoField#DAY_OF_WEEK ISO day-of-week} which are based on the {@linkplain ChronoField#EPOCH_DAY epoch-day} and the chronology. The values may not be aligned with the {@linkplain ChronoField#YEAR_OF_ERA year-of-Era} depending on the Chronology. !(p)A week is defined by: !(ul) !(li)The first day-of-week. For example, the ISO-8601 standard considers Monday to be the first day-of-week. !(li)The minimal number of days _in the first week. For example, the ISO-8601 standard counts the first week as needing at least 4 days. </ul> Together these two values allow a year or month to be divided into weeks.