Convert Joda-Time DateTime into Calendar and Vice Versa in Java

In this Joda-Time tutorial, we learn how to convert Joda-Time’s DateTime object into java.util.Calendar object and vice versa from java.util.Calendar object into Joda-Time’s DateTime object in Java.

Add Joda Time library to your Java project

To use Joda Time Java library in the Gradle build project, add the following dependency into the build.gradle file.

compile group: 'joda-time', name: 'joda-time', version: '2.10.9'

To use Joda Time Java library in the Maven build project, add the following dependency into the pom.xml file.

<dependency>
    <groupId>joda-time</groupId>
    <artifactId>joda-time</artifactId>
    <version>2.10.9</version>
</dependency>

To download the Joda Time .jar file you can visit Joda Time releases page at github.com/JodaOrg/joda-time

Convert DateTime into Calendar using DateTime.toCalendar() method

DateTimeToCalendar.java

import org.joda.time.DateTime;

import java.util.Calendar;
import java.util.Locale;

public class DateTimeToCalendar {
    public static void main(String[] args) {
        DateTime dateTime = DateTime.now();

        Calendar calendar = dateTime.toCalendar(Locale.getDefault());

        System.out.println(calendar.toString());
    }
}

The output is:

java.util.GregorianCalendar[time=1610984963653,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="Asia/Bangkok",offset=25200000,dstSavings=0,useDaylight=false,transitions=3,lastRule=null],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2021,MONTH=0,WEEK_OF_YEAR=4,WEEK_OF_MONTH=4,DAY_OF_MONTH=18,DAY_OF_YEAR=18,DAY_OF_WEEK=2,DAY_OF_WEEK_IN_MONTH=3,AM_PM=1,HOUR=10,HOUR_OF_DAY=22,MINUTE=49,SECOND=23,MILLISECOND=653,ZONE_OFFSET=25200000,DST_OFFSET=0]

Create New Calendar object from DateTime object using constructor

CalendarToDateTime.java

import org.joda.time.DateTime;

import java.util.Calendar;

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

        DateTime dateTime = new DateTime(calendar);

        System.out.println(dateTime);
    }
}