LocalDate withDayOfMonth() method in Java with Examples

The withDayOfMonth() method of LocalDate class in Java returns a copy of this LocalDate with the day-of-month altered.

Syntax:

public LocalDate withDayOfMonth(int dayOfMonth)

Parameter: This method accepts a mandatory parameter dayOfMonth whicthe day-of-month to set in the result, from 1 to 28-31.

Returns: The function returns a LocalDate based on this date with the requested day, not null.

Exceptions: The function throws a DateTimeException when the day of the month value is invalid.

Below programs illustrate the LocalDate.withDayOfMonth() method:

Program 1:

// Program to illustrate the withDayOfMonth() method

import java.util.*;
import java.time.*;

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

        // Parses the date
        LocalDate dt1 = LocalDate.parse("2018-12-07");
        LocalDate result = dt1.withDayOfMonth(01);

        // Prints the date with year
        System.out.println("The date with day of the month is: " + result);
    }
}

Output:

The date with day of the month is: 2018-12-01

Program 2:

// Program to illustrate the withDayOfMonth() method
// Exceptions
import java.util.*;
import java.time.*;
import java.time.temporal.ChronoField;

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

        try {
            // Parses the date
            LocalDate dt1 = LocalDate.parse("2018-12-07");
            LocalDate result = dt1.withDayOfMonth(35);

            // Prints the date with year
            System.out.println("The date with day of the month is: " + result);
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

java.time.DateTimeException: Invalid value for DayOfMonth (valid values 1 - 28/31): 35

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