Java Convert date and time between timezone

In this tutorial, we will show you few examples (ZonedDateTime (Java 8), Date, Calendar and Joda Time) to convert a date and time between different time zones.

All examples will be converting the date and time from

(UTC+8:00) Asia/Singapore - Singapore Time
Date : 22-1-2015 10:15:55 AM

to

(UTC-5:00) America/New_York - Eastern Standard Time
Date : 21-1-2015 09:15:55 PM

1. ZonedDateTime

Always use this new Java 8 java.time.ZonedDateTime to represent a date and time containing time zone.

package com.mkyong.date;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
public class ZonedDateTimeExample {
    private static final String DATE_FORMAT = "dd-M-yyyy hh:mm:ss a";
    public static void main(String[] args) {
        String dateInString = "22-1-2015 10:15:55 AM";
        LocalDateTime ldt = LocalDateTime.parse(dateInString, DateTimeFormatter.ofPattern(DATE_FORMAT));
        ZoneId singaporeZoneId = ZoneId.of("Asia/Singapore");
        System.out.println("TimeZone : " + singaporeZoneId);
        //LocalDateTime + ZoneId = ZonedDateTime
        ZonedDateTime asiaZonedDateTime = ldt.atZone(singaporeZoneId);
        System.out.println("Date (Singapore) : " + asiaZonedDateTime);
        ZoneId newYokZoneId = ZoneId.of("America/New_York");
        System.out.println("TimeZone : " + newYokZoneId);
        ZonedDateTime nyDateTime = asiaZonedDateTime.withZoneSameInstant(newYokZoneId);
        System.out.println("Date (New York) : " + nyDateTime);
        DateTimeFormatter format = DateTimeFormatter.ofPattern(DATE_FORMAT);
        System.out.println("\n---DateTimeFormatter---");
        System.out.println("Date (Singapore) : " + format.format(asiaZonedDateTime));
        System.out.println("Date (New York) : " + format.format(nyDateTime));

Output

TimeZone : Asia/Singapore
Date (Singapore) : 2015-01-22T10:15:55+08:00[Asia/Singapore]
TimeZone : America/New_York
Date (New York) : 2015-01-21T21:15:55-05:00[America/New_York]
---DateTimeFormatter---
Date (Singapore) : 22-1-2015 10:15:55 AM
Date (New York) : 21-1-2015 09:15:55 PM

2. Date

2.1 Set a time zone to DateFormat and format the java.util.Date

SimpleDateFormat sdfAmerica = new SimpleDateFormat("dd-M-yyyy hh:mm:ss a");
sdfAmerica.setTimeZone(TimeZone.getTimeZone("America/New_York"));
String sDateInAmerica = sdfAmerica.format(date);

2.2 Full example

package com.mkyong.date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
public class DateExample {
    private static final String DATE_FORMAT = "dd-M-yyyy hh:mm:ss a";
    public static void main(String[] args) throws ParseException {
        SimpleDateFormat formatter = new SimpleDateFormat(DATE_FORMAT);
        String dateInString = "22-01-2015 10:15:55 AM";
        Date date = formatter.parse(dateInString);
        TimeZone tz = TimeZone.getDefault();
        // From TimeZone Asia/Singapore
        System.out.println("TimeZone : " + tz.getID() + " - " + tz.getDisplayName());
        System.out.println("TimeZone : " + tz);
        System.out.println("Date (Singapore) : " + formatter.format(date));
        // To TimeZone America/New_York
        SimpleDateFormat sdfAmerica = new SimpleDateFormat(DATE_FORMAT);
        TimeZone tzInAmerica = TimeZone.getTimeZone("America/New_York");
        sdfAmerica.setTimeZone(tzInAmerica);
        String sDateInAmerica = sdfAmerica.format(date); // Convert to String first
        Date dateInAmerica = formatter.parse(sDateInAmerica); // Create a new Date object
        System.out.println("\nTimeZone : " + tzInAmerica.getID() + " - " + tzInAmerica.getDisplayName());
        System.out.println("TimeZone : " + tzInAmerica);
        System.out.println("Date (New York) (String) : " + sDateInAmerica);
        System.out.println("Date (New York) (Object) : " + formatter.format(dateInAmerica));

Output

TimeZone : Asia/Kuala_Lumpur - Malaysia Time
TimeZone : sun.util.calendar.ZoneInfo[id="Asia/Kuala_Lumpur",...]
Date (Singapore) : 22-1-2015 10:15:55 AM
TimeZone : America/New_York - Eastern Standard Time
TimeZone : sun.util.calendar.ZoneInfo[id="America/New_York",...]
Date (New York) (String) : 21-1-2015 09:15:55 PM
Date (New York) (Object) : 21-1-2015 09:15:55 PM

3. Calendar

3.1 A Calendar example to set a time zone :

	Calendar calendar = new GregorianCalendar();
	calendar.setTime(date);
	calendar.setTimeZone(tzInAmerica);

A super common mistake is to get the java.util.Date directly like this :

	//Wrong, it will display 22-1-2015 10:15:55 AM, time is still in the system default time zone!
	Date dateInAmerican = calendar.getTime()); 

In the above example, no matter what time zone you set in the Calendar, the Date object will be always printed with the default system time zone. (Check the Date.toString() source code)

3.2 The correct way should be using the DateFormat to format it :

	SimpleDateFormat sdfAmerica = new SimpleDateFormat("dd-M-yyyy hh:mm:ss a");
	TimeZone tzInAmerica = TimeZone.getTimeZone("America/New_York");
	sdfAmerica.setTimeZone(tzInAmerica);
	sdfAmerica.format(calendar.getTime())

or get the Date via calendar.get() :

	int year = calendar.get(Calendar.YEAR);
	int month = calendar.get(Calendar.MONTH); // Jan = 0, dec = 11
	int dayOfMonth = calendar.get(Calendar.DAY_OF_MONTH);
	int hour = calendar.get(Calendar.HOUR); // 12 hour clock
	int hourOfDay = calendar.get(Calendar.HOUR_OF_DAY); // 24 hour clock
	int minute = calendar.get(Calendar.MINUTE);
	int second = calendar.get(Calendar.SECOND);
	int ampm = calendar.get(Calendar.AM_PM); //0 = AM , 1 = PM

3.3 Full example

package com.mkyong.date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.TimeZone;
public class CalendarExample {
    private static final String DATE_FORMAT = "dd-M-yyyy hh:mm:ss a";
    public static void main(String[] args) throws ParseException {
        SimpleDateFormat formatter = new SimpleDateFormat(DATE_FORMAT);
        String dateInString = "22-01-2015 10:15:55 AM";
        Date date = formatter.parse(dateInString);
        TimeZone tz = TimeZone.getDefault();
        // From TimeZone Asia/Singapore
        System.out.println("TimeZone : " + tz.getID() + " - " + tz.getDisplayName());
        System.out.println("TimeZone : " + tz);
        System.out.println("Date (Singapore) : " + formatter.format(date));
        // To TimeZone America/New_York
        SimpleDateFormat sdfAmerica = new SimpleDateFormat(DATE_FORMAT);
        TimeZone tzInAmerica = TimeZone.getTimeZone("America/New_York");
        sdfAmerica.setTimeZone(tzInAmerica);
        Calendar calendar = new GregorianCalendar();
        calendar.setTime(date);
        calendar.setTimeZone(tzInAmerica);
        System.out.println("\nTimeZone : " + tzInAmerica.getID() + " - " + tzInAmerica.getDisplayName());
        System.out.println("TimeZone : " + tzInAmerica);
        //Wrong! It will print the date with the system default time zone
        System.out.println("Date (New York) (Wrong!): " + calendar.getTime());
        //Correct! need formatter
        System.out.println("Date (New York) (Correct!) : " + sdfAmerica.format(calendar.getTime()));
        int year = calendar.get(Calendar.YEAR);
        int month = calendar.get(Calendar.MONTH); // Jan = 0, dec = 11
        int dayOfMonth = calendar.get(Calendar.DAY_OF_MONTH);
        int hour = calendar.get(Calendar.HOUR); // 12 hour clock
        int hourOfDay = calendar.get(Calendar.HOUR_OF_DAY); // 24 hour clock
        int minute = calendar.get(Calendar.MINUTE);
        int second = calendar.get(Calendar.SECOND);
        int ampm = calendar.get(Calendar.AM_PM); //0 = AM , 1 = PM
        //Correct
        System.out.println("\nyear \t\t: " + year);
        System.out.println("month \t\t: " + month + 1);
        System.out.println("dayOfMonth \t: " + dayOfMonth);
        System.out.println("hour \t\t: " + hour);
        System.out.println("minute \t\t: " + minute);
        System.out.println("second \t\t: " + second);
        System.out.println("ampm \t\t: " + ampm);

Output

TimeZone : Asia/Kuala_Lumpur - Malaysia Time
TimeZone : sun.util.calendar.ZoneInfo[id="Asia/Kuala_Lumpur",...]
Date (Singapore) : 22-1-2015 10:15:55 AM
TimeZone : America/New_York - Eastern Standard Time
TimeZone : sun.util.calendar.ZoneInfo[id="America/New_York",...]]
Date (New York) (Wrong!): Thu Jan 22 10:15:55 MYT 2015
Date (New York) (Correct!) : 21-1-2015 09:15:55 PM
year 		: 2015
month 		: 01
dayOfMonth 	: 21
hour 		: 9
minute 		: 15
second 		: 55
ampm 		: 1

4. Joda Time

4.1 A Joda Time example to set a time zone :

	DateTime dt = new DateTime(date);
	DateTimeZone dtZone = DateTimeZone.forID("America/New_York");
	DateTime dtus = dt.withZone(dtZone);

Again, a common mistake is getting the Date directly like this, time zone will be lost.

	//Output : 22-1-2015 10:15:55 AM
	Date dateInAmerica = dtus.toDate();

The correct way is converted to Joda LocalDateTime first.

	//Output : 21-1-2015 09:15:55 PM
	Date dateInAmerica = dtus.toLocalDateTime().toDate();

4.2 Full example

package com.mkyong.date;
import org.joda.time.DateTime;
import org.joda.time.DateTimeZone;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
public class JodaTimeExample {
    private static final String DATE_FORMAT = "dd-M-yyyy hh:mm:ss a";
    public static void main(String[] args) throws ParseException {
        SimpleDateFormat formatter = new SimpleDateFormat(DATE_FORMAT);
        String dateInString = "22-01-2015 10:15:55 AM";
        Date date = formatter.parse(dateInString);
        TimeZone tz = TimeZone.getDefault();
        // From TimeZone Asia/Singapore
        System.out.println("TimeZone : " + tz.getID() + " - " + tz.getDisplayName());
        System.out.println("TimeZone : " + tz);
        System.out.println("Date (Singapore) : " + formatter.format(date));
        // To TimeZone America/New_York
        SimpleDateFormat sdfAmerica = new SimpleDateFormat(DATE_FORMAT);
        DateTime dt = new DateTime(date);
        DateTimeZone dtZone = DateTimeZone.forID("America/New_York");
        DateTime dtus = dt.withZone(dtZone);
        TimeZone tzInAmerica = dtZone.toTimeZone();
        Date dateInAmerica = dtus.toLocalDateTime().toDate(); //Convert to LocalDateTime first
        sdfAmerica.setTimeZone(tzInAmerica);
        System.out.println("\nTimeZone : " + tzInAmerica.getID() + " - " + tzInAmerica.getDisplayName());
        System.out.println("TimeZone : " + tzInAmerica);
        System.out.println("DateTimeZone : " + dtZone);
        System.out.println("DateTime : " + dtus);
        System.out.println("dateInAmerica (Formatter) : " + formatter.format(dateInAmerica));
        System.out.println("dateInAmerica (Object) : " + dateInAmerica);

Output

TimeZone : Asia/Kuala_Lumpur - Malaysia Time
TimeZone : sun.util.calendar.ZoneInfo[id="Asia/Kuala_Lumpur",...]
Date (Singapore) : 22-1-2015 10:15:55 AM
TimeZone : America/New_York - Eastern Standard Time
TimeZone : sun.util.calendar.ZoneInfo[id="America/New_York",...]
DateTimeZone : America/New_York
DateTime : 2015-01-21T21:15:55.000-05:00
dateInAmerica (Formatter) : 21-1-2015 09:15:55 PM
dateInAmerica (Object) : Wed Jan 21 21:15:55 MYT 2015

P.S Tested with Joda-time 2.9.4

References

1. Date and Time Manipulation in Java Using JodaTime
2. World Time Server
3. Java 8 – ZonedDateTime examples
4. Java 8 – Convert Date to LocalDate and LocalDateTime
5. ZonedDateTime Javadoc
6. Calendar JavaDoc
7. Date JavaDoc
8. SimpledateFormat JavaDoc