Java Convert Calendar to ZonedDateTime

Tags: Java Calendar Java ZonedDateTime Java 8

In this Java core tutorial we learn how to convert a java.util.Calendar object to a java.time.ZonedDateTime object in Java programming language.

How to convert Calendar to ZonedDateTime in Java

In Java, with a given Calendar object you can follow these steps to convert it to a ZonedDateTime object.

  • Step 1: convert Calendar object to Instant object using Calendar.toInstant() method.
  • Step 2: Use the ZonedDateTime.ofInstant(Instant instant, ZoneId zone) method to convert the above Instant object to ZonedDateTime object in system default time zone.

import java.time.Instant;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.util.Calendar;
import java.util.TimeZone;

public class ConvertCalendarToZonedDateTimeExample1 {
    public static void main(String... args) {
        Calendar calendar = Calendar.getInstance();

        Instant instant = calendar.toInstant();
        ZoneId zoneId = TimeZone.getDefault().toZoneId();
        ZonedDateTime zonedDateTime = ZonedDateTime.ofInstant(instant, zoneId);

        System.out.println("Calendar year: " + calendar.get(Calendar.YEAR));
        System.out.println("Calendar month (0 to 11): " + calendar.get(Calendar.MONTH));
        System.out.println("Calendar day of month: " + calendar.get(Calendar.DAY_OF_MONTH));
        System.out.println("Calendar hour: " + calendar.get(Calendar.HOUR_OF_DAY));
        System.out.println("Calendar minute: " + calendar.get(Calendar.MINUTE));
        System.out.println("Calendar second: " + calendar.get(Calendar.SECOND));
        System.out.println("Calendar millisecond: " + calendar.get(Calendar.MILLISECOND));
        System.out.println("ZonedDateTime: " + zonedDateTime);
The output as below.
Calendar year: 2022
Calendar month (0 to 11): 4
Calendar day of month: 20
Calendar hour: 0
Calendar minute: 46
Calendar second: 30
Calendar millisecond: 429
ZonedDateTime: 2022-05-20T00:46:30.429+07:00[Asia/Bangkok]

Happy Coding 😊

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