DayOfWeek adjustInto() method in Java with Examples

The adjustInto() method of java.time.DayOfWeek is an in-built function in Java which takes a Temporal object specifying a date and returns a new Temporal object of the same observable type as the input with the day-of-week changed to be the same as specified DayOfWeek constant. Note that this method adjusts forwards or backwards within a Monday to Sunday week.

Method Declaration:

 public Temporal adjustInto(Temporal temporal)

Syntax:

 Temporal newLocalDate = DayOfWeek.ANYWEEKDAY.adjustInto(Temporal temporal)

Parameters: This method takes temporal as parameter where:

temporal – is the specified date to be adjusted.

ANYWEEKDAY – is the specified day to which the date is to be adjusted, e.g., MONDAY, TUESDAY, etc.

newLocalDate – is the modified date.

Return Value: The function returns an adjusted Temporal object which is the date adjusted according to specified Day of the Week.

Below programs illustrate the above method:
Program 1:

import java.time.*;
import java.time.DayOfWeek;
import java.time.temporal.Temporal;

class DayOfWeekExample {
    public static void main(String[] args)
    {
        // Set a Local Date whose day is found
        LocalDate localDate1
            = LocalDate.of(1947, Month.AUGUST, 15);

        // Find the day from the Local Date
        DayOfWeek dayOfWeek1
            = DayOfWeek.from(localDate1);

        // Printing the Local Date
        System.out.println(localDate1
                           + " which is "
                           + dayOfWeek1.name());

        // Adjust the Date to Monday from Friday
        Temporal localDate2
            = DayOfWeek.MONDAY
                  .adjustInto(localDate1);

        // Find the day from the new Local date
        DayOfWeek dayOfWeek2
            = DayOfWeek.from(localDate2);

        // Printing the new Local Date
        System.out.println(localDate2
                           + " which is "
                           + dayOfWeek2.name());
    }
}

Output:

1947-08-15 which is FRIDAY
1947-08-11 which is MONDAY

Program 2:

import java.time.*;
import java.time.DayOfWeek;
import java.time.temporal.Temporal;

class DayOfWeekExample {
    public static void main(String[] args)
    {
        // Set a Local Date whose day is found
        LocalDate localDate1
            = LocalDate.of(2019, Month.MARCH, 18);

        // Find the day from the Local Date
        DayOfWeek dayOfWeek1
            = DayOfWeek.from(localDate1);

        // Printing the Local Date
        System.out.println(localDate1
                           + " which is "
                           + dayOfWeek1.name());

        // Adjust the Date to Wednesday from Monday
        Temporal localDate2
            = DayOfWeek.WEDNESDAY
                  .adjustInto(localDate1);

        // Find the day from the new Local date
        DayOfWeek dayOfWeek2
            = DayOfWeek.from(localDate2);

        // Printing the new Local Date
        System.out.println(localDate2
                           + " which is "
                           + dayOfWeek2.name());
    }
}

Output:

2019-03-18 which is MONDAY
2019-03-20 which is WEDNESDAY

Reference: https://docs.oracle.com/javase/8/docs/api/java/time/DayOfWeek.html#adjustInto-java.time.temporal.Temporal-