@Nullable
    public static DayOfTheWeek valueOf(@Nullable final DayOfWeek dayOfWeek) {
        if (dayOfWeek == null) {
            return null;
        }
        final int value = dayOfWeek.getValue();
        for (final DayOfTheWeek dow : ALL) {
            if (value == dow.id) {
                return dow;
            }
        }
        throw new IllegalArgumentException("Unknown day week: " + dayOfWeek);
    }
@ Nullable public static DayOfTheWeek valueOf ( @ Nullable final DayOfWeek dayOfWeek ) { if ( dayOfWeek == null ) { return null ; } final int value = dayOfWeek . getValue ( ) ; for ( final DayOfTheWeek dow : ALL ) { if ( value == dow . id ) { return dow ; } } throw new IllegalArgumentException ( "Unknown day week: " + dayOfWeek ) ; }
Converts the instance into java time instance.

@return Day of week.