import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.Month;
import java.time.temporal.TemporalAdjusters;
import java.time.temporal.WeekFields;
import java.util.Locale;
 
public class Main {
    public static void main(String[] args) {
        // A sample LocalDate
        LocalDate date = LocalDate.of(2011, Month.JANUARY, 21);
 
        LocalDate dateOnSameOrPreviousMon = date.with(
                TemporalAdjusters.previousOrSame(DayOfWeek.MONDAY));
 
        LocalDate dateOnSameOrNextSun = date.with(
                TemporalAdjusters.nextOrSame(DayOfWeek.SUNDAY));
 
        System.out.println(dateOnSameOrPreviousMon);
        System.out.println(dateOnSameOrNextSun);
 
        // ###### The first day of the week is Locale-sensitive ######
        LocalDate now = LocalDate.now();
 
        // First day of a week in the US is Sunday
        DayOfWeek firstDayOfWeekUs = now
                .with(WeekFields.of(Locale.US).dayOfWeek(), 1)
                .getDayOfWeek();
        System.out.println(firstDayOfWeekUs);
 
        // First day of a week in the UK is Monday
        DayOfWeek firstDayOfWeekUk = now
                .with(WeekFields.of(Locale.UK).dayOfWeek(), 1)
                .getDayOfWeek();
        System.out.println(firstDayOfWeekUk);
 
        // ###### Thus, the first and last days of the week of the given date:
 
        // In the US
        LocalDate dateOnFirstDayOfWeekUs = date.with(
                TemporalAdjusters.previousOrSame(firstDayOfWeekUs));
        LocalDate dateOnLaststDayOfWeekUs = dateOnFirstDayOfWeekUs.plusDays(6);
        System.out.println(dateOnFirstDayOfWeekUs);
        System.out.println(dateOnLaststDayOfWeekUs);
 
        // In the UK
        LocalDate dateOnFirstDayOfWeekUk = date.with(
                TemporalAdjusters.previousOrSame(firstDayOfWeekUk));
        LocalDate dateOnLaststDayOfWeekUk = dateOnFirstDayOfWeekUk.plusDays(6);
        System.out.println(dateOnFirstDayOfWeekUk);
        System.out.println(dateOnLaststDayOfWeekUk);
    }
}