ZonedDateTime plusHours() method in Java with Examples

Last Updated : 10 Dec, 2018

plusHours() method of a ZonedDateTime class used to add the number of hours in this ZonedDateTime and return a copy of ZonedDateTime after addition.This operates on the instant time-line, such that adding one hour will always be a duration of one hour later. Adding one hour may cause the local date-time to change by an amount other than one hour. For example, consider a time-zone, such as 'Europe/Paris', where the Autumn DST cutover means that the local times 02:00 to 02:59 occur twice changing from offset +02:00 in summer to +01:00 in winter.

Adding one hour to 01:30+02:00 will result in 02:30+02:00 (both in summer time)
Adding one hour to 02:30+02:00 will result in 02:30+01:00 (moving from summer to winter time)
Adding one hour to 02:30+01:00 will result in 03:30+01:00 (both in winter time)
Adding three hours to 01:30+02:00 will result in 03:30+01:00 (moving from summer to winter time)

This instance is immutable and unaffected by this method call. Syntax:

public ZonedDateTime plusHours(long hours)

Parameters: This method accepts a single parameter hours which represents the hours to add, It can be negative. Return value: This method returns a ZonedDateTime based on this date-time with the hours added, not null. Exception: This method throws DateTimeException if the result exceeds the supported date range. Below programs illustrate the plusHours() method: Program 1:

Java

// Java program to demonstrate
// ZonedDateTime.plusHours() method

import java.time.*;

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

        // create a ZonedDateTime object
        ZonedDateTime zoneddatetime
            = ZonedDateTime.parse(
                "2018-12-06T19:21:12.123+05:30[Asia/Calcutta]");

        // print instance
        System.out.println("ZonedDateTime before"
                           + " adding hours: "
                           + zoneddatetime);

        // add 3 hours
        ZonedDateTime returnvalue
            = zoneddatetime.plusHours(3);

        // print result
        System.out.println("ZonedDateTime after "
                           + " adding hours: "
                           + returnvalue);
    }
}

Output:

ZonedDateTime before adding hours: 2018-12-06T19:21:12.123+05:30[Asia/Calcutta] ZonedDateTime after adding hours: 2018-12-06T22:21:12.123+05:30[Asia/Calcutta]

Program 2:

Java

// Java program to demonstrate
// ZonedDateTime.plusHours() method

import java.time.*;

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

        // create a ZonedDateTime object
        ZonedDateTime zoneddatetime
            = ZonedDateTime.parse(
                "2018-10-25T23:12:31.123+02:00[Europe/Paris]");

        // print instance
        System.out.println("ZonedDateTime before"
                           + " adding hours: "
                           + zoneddatetime);

        // add 20 hours
        ZonedDateTime returnvalue
            = zoneddatetime.plusHours(20);

        // print result
        System.out.println("ZonedDateTime after "
                           + " adding hours: "
                           + returnvalue);
    }
}

Output:

ZonedDateTime before adding hours: 2018-10-25T23:12:31.123+02:00[Europe/Paris] ZonedDateTime after adding hours: 2018-10-26T19:12:31.123+02:00[Europe/Paris]

Reference: https://docs.oracle.com/javase/10/docs/api/java/time/ZonedDateTime.html#plusHours(long)