Convert Instant to ZonedDateTime in JAVA

In this tutorial , we will show a Java 8 example of how to convert from Instant to ZonedDateTime

import java.time.Instant;
import java.time.ZoneId;
import java.time.ZonedDateTime;

public class InstantZonedDateTime1 {

    public static void main(String[] argv) {

        // Z = UTC+0
        Instant instant = Instant.now();

        System.out.println("Instant : " + instant);

        // Japan = UTC+9
        ZonedDateTime jpTime = instant.atZone(ZoneId.of("Asia/Tokyo"));

        System.out.println("ZonedDateTime : " + jpTime);

        System.out.println("OffSet : " + jpTime.getOffset());

    }

}

So the output will be :

Instant : 2016-08-18T06:17:10.225Z
LocalDateTime : 2016-08-18T06:17:10.225

If we need to convert from ZonedDateTime to Instant

import java.time.*;

public class InstantZonedDateTime2 {

    public static void main(String[] argv) {

        LocalDateTime dateTime = LocalDateTime.of(2016, Month.AUGUST, 18, 6, 57, 38);

        // UTC+9
        ZonedDateTime jpTime = dateTime.atZone(ZoneId.of("Asia/Tokyo"));

        System.out.println("ZonedDateTime : " + jpTime);

        // Convert to instant UTC+0/Z , java.time helps to reduce 9 hours
        Instant instant = jpTime.toInstant();

        System.out.println("Instant : " + instant);

    }

}

The output will be :

ZonedDateTime : 2016-08-18T06:57:38+09:00[Asia/Tokyo]
Instant : 2016-08-17T21:57:38Z

Also read : How to convert String to Date in Java ?

References :

• JavaDoc
• mkYong