MonthDay withDayOfMonth() Method in Java with Examples

withDayOfMonth(int dayOfMonth) method of the MonthDay class used to alter the day-of-month of MonthDay object using dayOfMonth passed as a parameter and after that method returns the copy of altered MonthDay.An exception is thrown If the day-of-month value is invalid for the specified month after altering operation.

Syntax:

public MonthDay withDayOfMonth(int dayOfMonth)

Parameters: This method accepts dayOfMonth as parameter which is the day-of-month to set in the return month-day, from 1 to 31.

Return value: This method returns a MonthDay based on this month-day with the requested day.

Exception: This method throws DateTimeException if the day-of-month value is invalid, or if the day-of-month is invalid for the month.

Below programs illustrate the withDayOfMonth() method:
Program 1:

// Java program to demonstrate
// MonthDay.withDayOfMonth() method

import java.time.*;
import java.time.temporal.*;

public class GFG {
    public static void main(String[] args)
    {

        // create a MonthDay object
        MonthDay monthday
            = MonthDay.of(8, 28);

        // print instance
        System.out.println("MonthDay before"
                           + " applying method: "
                           + monthday);

        // apply withDayOfMonth method
        // of MonthDay class
        MonthDay updatedlocal
            = monthday.withDayOfMonth(21);

        // print instance
        System.out.println("MonthDay after"
                           + " applying method: "
                           + updatedlocal);
    }
}

Output:

MonthDay before applying method: --08-28
MonthDay after applying method: --08-21

Program 2:

// Java program to demonstrate
// MonthDay.withDayOfMonth() method

import java.time.*;
import java.time.temporal.*;

public class GFG {
    public static void main(String[] args)
    {

        // create a MonthDay object
        MonthDay monthday
            = MonthDay.of(10, 31);

        // print instance
        System.out.println("MonthDay before"
                           + " applying method: "
                           + monthday);

        // apply withDayOfMonth method
        // of MonthDay class
        MonthDay updatedlocal
            = monthday.withDayOfMonth(12);

        // print instance
        System.out.println("MonthDay after"
                           + " applying method: "
                           + updatedlocal);
    }
}

Output:

MonthDay before applying method: --10-31
MonthDay after applying method: --10-12

References: https://docs.oracle.com/javase/10/docs/api/java/time/MonthDay.html#withDayOfMonth(int)