Java MonthDay atYear() Method

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The atYear() method in Java, part of the java.time.MonthDay class, returns a LocalDate object formed from the month-day and the specified year. This method is useful for creating a complete date from a month-day and a year.

Table of Contents

1. Introduction
2. atYear() Method Syntax
3. Understanding atYear()
4. Examples
   • Basic Usage
   • Using atYear() in Conditional Statements
5. Real-World Use Case
6. Conclusion

Introduction

The atYear() method allows you to create a LocalDate instance by combining a MonthDay with a specified year. This is particularly useful when you need to construct a full date from a month-day and a year.

atYear() Method Syntax

The syntax for the atYear() method is as follows:

public LocalDate atYear(int year)

Parameters:

• year: The year to use, from Year.MIN_VALUE to Year.MAX_VALUE.

Returns:

• A LocalDate formed from the month-day and the specified year, not null.

Throws:

• DateTimeException if the day-of-month is invalid for the specified year.

Understanding atYear()

The atYear() method combines the MonthDay instance with the specified year to create a LocalDate. This is useful for handling scenarios where you need to work with month-day combinations and then convert them into full dates by specifying a year.

Examples

Basic Usage

To demonstrate the basic usage of atYear(), we will create a LocalDate from a MonthDay and a specified year.

Example

import java.time.LocalDate;
import java.time.MonthDay;

public class MonthDayAtYearExample {
    public static void main(String[] args) {
        MonthDay monthDay = MonthDay.of(6, 15); // June 15
        int year = 2023;
        LocalDate date = monthDay.atYear(year);

        System.out.println("MonthDay: " + monthDay);
        System.out.println("Year: " + year);
        System.out.println("LocalDate: " + date);
    }
}

Output:

MonthDay: --06-15
Year: 2023
LocalDate: 2023-06-15

Using atYear() in Conditional Statements

This example shows how to use the atYear() method in conditional statements to perform actions based on the resulting LocalDate.

Example

import java.time.LocalDate;
import java.time.MonthDay;

public class MonthDayConditionalExample {
    public static void main(String[] args) {
        MonthDay monthDay = MonthDay.of(2, 29); // February 29
        int year = 2024; // Leap year
        LocalDate date = monthDay.atYear(year);

        if (date.isLeapYear()) {
            System.out.println(date + " is in a leap year.");
        } else {
            System.out.println(date + " is not in a leap year.");
        }
    }
}

Output:

2024-02-29 is in a leap year.

Real-World Use Case

Scheduling Recurring Events

In real-world applications, the atYear() method can be used to schedule recurring events by combining a MonthDay with different years.

Example

import java.time.LocalDate;
import java.time.MonthDay;

public class EventSchedulerExample {
    public static void main(String[] args) {
        MonthDay eventMonthDay = MonthDay.of(12, 25); // December 25
        int[] years = {2023, 2024, 2025};

        System.out.println("Scheduled events:");
        for (int year : years) {
            LocalDate eventDate = eventMonthDay.atYear(year);
            System.out.println(eventDate);
        }
    }
}

Output:

Scheduled events:
2023-12-25
2024-12-25
2025-12-25

Conclusion

The MonthDay.atYear() method is used to create a LocalDate instance by combining a MonthDay with a specified year. This method is particularly useful for constructing full dates from month-day combinations and years. By understanding and using the atYear() method, you can effectively manage and manipulate date-related data in your Java applications.