java.time.YearMonth Class in Java

Last Updated : 9 Sep, 2026

The YearMonth class in Java represents a combination of a year and a month, such as 2026-09. It is an immutable date-time class and does not store a day, time, or time zone.

  • YearMonth belongs to the java.time package and implements Temporal, TemporalAdjuster, Comparable<YearMonth>, and Serializable.
  • It provides methods to create, compare, modify, format, and retrieve information about a year and month.

Example: The program creates a YearMonth object for September 2026 and retrieves information about the month.

Java 
import java.time.YearMonth;

public class GFG {
    public static void main(String[] args) {
        YearMonth ym = YearMonth.of(2026, 9);

        System.out.println("Year-Month: " + ym);
        System.out.println("Month: " + ym.getMonth());
        System.out.println("Days in month: " + ym.lengthOfMonth());
    }
}

Output
Year-Month: 2026-09
Month: SEPTEMBER
Days in month: 30

Explanation: YearMonth.of() creates the object, while getMonth() and lengthOfMonth() retrieve its month and number of days.

Syntax

public final class YearMonth
implements Temporal, TemporalAdjuster,
Comparable<YearMonth>, Serializable

Ways to Use YearMonth

1. Using plus()

The plus() method returns a new YearMonth with the specified amount added. The original object remains unchanged.

Syntax

public YearMonth plus(TemporalAmount amountToAdd)

Java 
import java.time.Period;
import java.time.YearMonth;

public class GFG {
    public static void main(String[] args) {
        YearMonth ym = YearMonth.of(2021, 2);

        YearMonth result = ym.plus(Period.ofYears(3));

        System.out.println("Original: " + ym);
        System.out.println("After adding: " + result);
    }
}

Output
Original: 2021-02
After adding: 2024-02

Explanation: plus() adds three years to the YearMonth and returns a new object.

2. Using minus()

The minus() method returns a new YearMonth with the specified amount subtracted.

Syntax

public YearMonth minus(TemporalAmount amountToSubtract)

Java 
import java.time.Period;
import java.time.YearMonth;

public class GFG {
    public static void main(String[] args) {
        YearMonth ym = YearMonth.of(2021, 2);

        YearMonth result = ym.minus(Period.ofYears(3));

        System.out.println("Original: " + ym);
        System.out.println("After subtracting: " + result);
    }
}

Output
Original: 2021-02
After subtracting: 2018-02

Explanation: minus() subtracts three years from the YearMonth and returns a new object.

Commonly Used Methods

Method Description
of()Creates a YearMonth from a year and month.
now()Obtains the current year and month.
parse()Creates a YearMonth from a text value.
plusMonths()Adds the specified number of months.
plusYears()Adds the specified number of years.
minusMonths()Subtracts the specified number of months.
minusYears()Subtracts the specified number of years.
plus()Returns a copy with the specified amount added.
minus()Returns a copy with the specified amount subtracted.
atDay()Combines the year-month with a day to create a LocalDate.
atEndOfMonth()Returns the last day of the month as a LocalDate.
getYear()Returns the year.
getMonth()Returns the month as a Month enum.
getMonthValue()Returns the month number from 1 to 12.
isLeapYear()Checks whether the year is a leap year.
isValidDay()Checks whether a day is valid for the year-month.
lengthOfMonth()Returns the number of days in the month.
lengthOfYear()Returns the number of days in the year.
isAfter()Checks whether this year-month is after another.
isBefore()Checks whether this year-month is before another.
compareTo()Compares two YearMonth objects.
format()Formats the year-month using a formatter.
equals()Checks whether two YearMonth objects are equal.
hashCode()Returns the hash code of the year-month.
toString()Returns the year-month as a string.
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