Java Month firstDayOfYear() Method

The firstDayOfYear() method in Java, part of the java.time.Month enum, returns the ordinal day of the first day of the specified month in a standard year (non-leap year). This method is useful for determining the position of the first day of any month within the year.

Table of Contents

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

Introduction

The firstDayOfYear() method allows you to find out the ordinal day of the first day of a specified month in a non-leap year. This is particularly useful when you need to calculate the position of the first day of a month within a year.

firstDayOfYear() Method Syntax

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

public int firstDayOfYear(boolean leapYear)

Parameters:

• leapYear: A boolean value indicating whether the year is a leap year (true) or not (false).

Returns:

• An int representing the ordinal day of the first day of the specified month within the year.

Throws:

• This method does not throw any exceptions.

Understanding firstDayOfYear()

The firstDayOfYear() method calculates the ordinal day of the first day of the month for a standard year or a leap year based on the boolean parameter passed. In a standard year, February has 28 days, while in a leap year, it has 29 days.

Examples

Basic Usage

To demonstrate the basic usage of firstDayOfYear(), we will get the first day of the year for various months.

Example

import java.time.Month;

public class MonthFirstDayOfYearExample {
    public static void main(String[] args) {
        for (Month month : Month.values()) {
            int firstDayStandardYear = month.firstDayOfYear(false); // Standard year
            int firstDayLeapYear = month.firstDayOfYear(true); // Leap year

            System.out.println(month + " - First day of the year (standard year): " + firstDayStandardYear);
            System.out.println(month + " - First day of the year (leap year): " + firstDayLeapYear);
        }
    }
}

Output:

JANUARY - First day of the year (standard year): 1
JANUARY - First day of the year (leap year): 1
FEBRUARY - First day of the year (standard year): 32
FEBRUARY - First day of the year (leap year): 32
MARCH - First day of the year (standard year): 60
MARCH - First day of the year (leap year): 61
APRIL - First day of the year (standard year): 91
APRIL - First day of the year (leap year): 92
MAY - First day of the year (standard year): 121
MAY - First day of the year (leap year): 122
JUNE - First day of the year (standard year): 152
JUNE - First day of the year (leap year): 153
JULY - First day of the year (standard year): 182
JULY - First day of the year (leap year): 183
AUGUST - First day of the year (standard year): 213
AUGUST - First day of the year (leap year): 214
SEPTEMBER - First day of the year (standard year): 244
SEPTEMBER - First day of the year (leap year): 245
OCTOBER - First day of the year (standard year): 274
OCTOBER - First day of the year (leap year): 275
NOVEMBER - First day of the year (standard year): 305
NOVEMBER - First day of the year (leap year): 306
DECEMBER - First day of the year (standard year): 335
DECEMBER - First day of the year (leap year): 336

Using firstDayOfYear() in Conditional Statements

This example shows how to use the firstDayOfYear() method in conditional statements to perform actions based on the ordinal day of the first day of the month.

Example

import java.time.Month;

public class MonthFirstDayConditionalExample {
    public static void main(String[] args) {
        Month month = Month.AUGUST;
        int firstDayStandardYear = month.firstDayOfYear(false); // Standard year

        if (firstDayStandardYear > 200) {
            System.out.println("The first day of " + month + " is after the 200th day of the year.");
        } else {
            System.out.println("The first day of " + month + " is on or before the 200th day of the year.");
        }
    }
}

Output:

The first day of AUGUST is after the 200th day of the year.

Real-World Use Case

Determining Fiscal Quarters

In real-world applications, the firstDayOfYear() method can be used to determine the starting days of fiscal quarters for financial calculations.

Example

import java.time.Month;

public class FiscalQuarterExample {
    public static void main(String[] args) {
        Month quarterStartMonth = Month.APRIL;
        int firstDayOfQuarter = quarterStartMonth.firstDayOfYear(false); // Standard year

        System.out.println("The fiscal quarter starting in " + quarterStartMonth + " begins on day " + firstDayOfQuarter + " of the year.");
    }
}

Output:

The fiscal quarter starting in APRIL begins on day 91 of the year.

Conclusion

The Month.firstDayOfYear() method is used to determine the ordinal day of the first day of a specified month within the year, either in a standard year or a leap year. By understanding and using the firstDayOfYear() method, you can effectively manage and manipulate date-related data in your Java applications.