question: private WeekFields ( DayOfWeek firstDayOfWeek , int minimalDaysInFirstWeek ) { Objects . requireNonNull ( firstDayOfWeek , "firstDayOfWeek" ) ; if ( minimalDaysInFirstWeek < 1 || minimalDaysInFirstWeek > 7 ) { throw new IllegalArgumentException ( "Minimal number of days is invalid" ) ; } this . firstDayOfWeek = firstDayOfWeek ; this . minimalDays = minimalDaysInFirstWeek ; }
target:  Creates an instance of the definition.