Develop Reference

How to get specific date UTC value in java

I am having string date in this formate (yyyy-MM-dd HH:mm:ss.SSS) how to convert this to UTC timestamp.

please try like this :
long time = 0;
try {
Date date1 = new Date((new Date()).getTime());
SimpleDateFormat formatNowDay = new SimpleDateFormat("dd", Locale.getDefault());
SimpleDateFormat formatNowMonth = new SimpleDateFormat("MM", Locale.getDefault());
SimpleDateFormat formatNowHours = new SimpleDateFormat("HH", Locale.getDefault());
SimpleDateFormat formatNowMinute = new SimpleDateFormat("mm", Locale.getDefault());
SimpleDateFormat formatNowSecond = new SimpleDateFormat("ss", Locale.getDefault());
SimpleDateFormat formatGMT = new SimpleDateFormat("zzz", Locale.getDefault());
String currentDay = formatNowDay.format(date1);
String currentMonth = formatNowMonth.format(date1);
String currentHours = formatNowHours.format(date1);
String currentMinute = formatNowMinute.format(date1);
String currentSecond = formatNowSecond.format(date1);
String GMT = formatGMT.format(date1);
String str_date = currentDay + currentMonth + "1970" + currentHours + currentMinute + currentSecond + GMT;
DateFormat formatter = new SimpleDateFormat("ddMMyyyyHHmmsszzz", Locale.getDefault());
Date date = formatter.parse(str_date);
time = (date.getTime() / 1000L);
} catch (ParseException e) {
e.printStackTrace();
}
return String.valueOf(time);
}

The format you have mentioned does not have the timezone information. Therefore, first, you should parse it to a LocalDateTime using a DateTimeFormatter and then convert this LocalDateTime for ZoneOffset.UTC to an Instant.
Demo:
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
public class Main {
public static void main(String[] args) {
// A sample date-time string
String dateStr = "2020-02-29 19:56:36.234";
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS", Locale.ENGLISH);
LocalDateTime ldt = LocalDateTime.parse(dateStr, dtf);
Instant instant = ldt.toInstant(ZoneOffset.UTC);
System.out.println(instant);
}
}
Output:
2020-02-29T19:56:36.234Z
ONLINE DEMO
An Instant represents an instantaneous point on the timeline in UTC. The Z in the output is the timezone designator for a zero-timezone offset. It stands for Zulu and specifies the Etc/UTC timezone (which has the timezone offset of +00:00 hours).
Note: The java.util Date-Time API and their formatting API, SimpleDateFormat are outdated and error-prone. It is recommended to stop using them completely and switch to the modern Date-Time API*. For any reason, if you need to convert this object of Instant to an object of java.util.Date, you can do so as follows:
Date date = Date.from(instant);
Learn more about the modern Date-Time API from Trail: Date Time.
* For any reason, if you have to stick to Java 6 or Java 7, you can use ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and How to use ThreeTenABP in Android Project.

Why Calendar and SimpleDateFormat are showing a bad date?

I try to parse a date from a string but when I print it, it shows a bad date. My code:
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.text.SimpleDateFormat;
public class Main {
public static void main(String args[]) {
String some_date = "2017-12-31";
Calendar cal_aux = GregorianCalendar.getInstance();
System.out.println("set calendar: " + Integer.parseInt(some_date.substring(0, 4))
+ Integer.parseInt(some_date.substring(5, 7))
+ Integer.parseInt(some_date.substring(8, 10)));
cal_aux.set(Integer.parseInt(some_date.substring(0, 4)),
Integer.parseInt(some_date.substring(5, 7)),
Integer.parseInt(some_date.substring(8, 10)));
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
System.out.println("sdf calendar: " + sdf.format(cal_aux.getTime()));
}
}
Console output:
set calendar: 20171231
sdf calendar: 2018-01-31 12:51:02
Why when I use the simple date format I'm getting 2018 instead of 2017?

Avoid the legacy date-time classes now supplanted by java.time classes. The problematic legacy classes have many design faults. One such fault is counting months as 0-11 rather than 1-12. This crazy counting is breaking your code.
Do not manipulate date-time values as strings. Use objects.
For that date-only value use LocalDate.
LocalDate ld = LocalDate.parse( "2017-12-31" ) ; // Or LocalDate.now() for today's date.
Generate a String by using a DateTimeFormatter.
String output = ld.format( DateTimeFormatter.BASIC_ISO_DATE ) ;
20171231
Assign a time-of-day if desired.
LocalTime lt = LocalTime.of( 6 , 15 ) ;
LocalDateTime ltd = LocalDateTime.of( ld , lt ) ;
Apply a time zone if you want an actual moment, a specific point on the timeline.
ZoneId z = ZoneId.of( "Africa/Casablanca" ) ;
ZonedDateTime zdt = ldt.atZone( z ) ;

First, you set wrong date because the month range is 0-11. When you set 12 in month field, is january 2018 instead december 2017.
Second, you can simplify your program parsing the input string to formatted date and parsing this date to output formatted string. Here is an example:
String input = "20171231";
SimpleDateFormat inputFormat = new SimpleDateFormat("yyyyMMdd");
SimpleDateFormat outputFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
try {
System.out.println(outputFormat.format(inputFormat.parse(input)));
} catch (ParseException e) {
// Log error
}

Why the time of AWST and CCT are not the same?

I have write a static class named"DateUtils" and here is a static method named "parseDate(String)" it will use some patterns to convert the string to a date.
the default timeZone is Asia/Shanghai (I'am in China)
public static final TimeZone SHA = TimeZone.getTimeZone("Asia/Shanghai");
and it will be passed to the method
TimeZone.setDefault(timeZone);
And Using SimpleDateFormat to concert the String.
The matched pattern should be "EEE, dd MMM yyyy HH:mm:ss zzz"
And Here are three Test of it.
//this one is ok.
#Test
public void testParseGMTDate() throws Exception {
Date date = DateUtils.parseDate("Thu, 02 Aug 2016 08:12:34 GMT");
assertNotNull(date);
Calendar cal = Calendar.getInstance();
cal.setTime(date);
log.debug(DateUtils.format(cal.getTime()));
assertEquals(cal.get(Calendar.YEAR), 2016);
assertEquals(cal.get(Calendar.MONTH), 8 - 1);
assertEquals(cal.get(Calendar.DATE), 2);
assertEquals(cal.get(Calendar.HOUR_OF_DAY), 8 + 8);
assertEquals(cal.get(Calendar.MINUTE), 12);
assertEquals(cal.get(Calendar.SECOND), 34);
assertEquals(DateUtils.format(cal.getTime()), "2016-08-02 16:12:34");
}
// AWST is GMS+8:00 time so this one is ok.
#Test
public void testParseWSTDate() throws Exception {
Date date = DateUtils.parseDate("Thu, 02 Aug 2016 08:12:34 AWST");
assertNotNull(date);
Calendar cal = Calendar.getInstance();
cal.setTime(date);
log.debug(DateUtils.format(cal.getTime()));
assertEquals(cal.get(Calendar.YEAR), 2016);
assertEquals(cal.get(Calendar.MONTH), 8 - 1);
assertEquals(cal.get(Calendar.DATE), 2);
assertEquals(cal.get(Calendar.HOUR_OF_DAY), 8);
assertEquals(cal.get(Calendar.MINUTE), 12);
assertEquals(cal.get(Calendar.SECOND), 34);
}
// junit.framework.AssertionFailedError:
// Expected :9
// Actual :8
#Test
public void testParseDateCCT() throws Exception {
Date date = DateUtils.parseDate("Thu, 02 Aug 2016 08:12:34 CCT");
assertNotNull(date);
Calendar cal = Calendar.getInstance();
cal.setTime(date);
log.debug(DateUtils.format(cal.getTime()));
assertEquals(cal.get(Calendar.YEAR), 2016);
assertEquals(cal.get(Calendar.MONTH), 8 - 1);
assertEquals(cal.get(Calendar.DATE), 2);
assertEquals(cal.get(Calendar.HOUR_OF_DAY), 8); //Expected: 9
assertEquals(cal.get(Calendar.MINUTE), 12);
assertEquals(cal.get(Calendar.SECOND), 34);
}
And here are some code snippet of DateUtils.
public static final TimeZone SHA = TimeZone.getTimeZone("Asia/Shanghai");
static {
Calendar calendar = Calendar.getInstance();
calendar.setTimeZone(SHA);
calendar.set(2000, 0, 1, 0, 0, 0);
calendar.set(MILLISECOND, 0);
TWO_DIGIT_START = calendar.getTime();
}
public static Date parseDate(String dateValue) {
return parseDate(dateValue, null, null, SHA);
}
public static Date parseDate(String dateValue, String[] dateFormats, Date startDate, TimeZone timeZone) {
TimeZone.setDefault(timeZone);
String[] localDateFormats = dateFormats != null ? dateFormats : DEFAULT_PATTERNS;
Date localStartDate = startDate != null ? startDate : TWO_DIGIT_START;
String v = dateValue;
if (dateValue.length() > 1 && dateValue.startsWith("\'") && dateValue.endsWith("\'")) {
v = dateValue.substring(1, dateValue.length() - 1);
}
String[] arr = localDateFormats;
int len = localDateFormats.length;
for (String dateFormat : DEFAULT_PATTERNS) {
// String dateFormat = arr[i];
SimpleDateFormat dateParser = DateUtils.DateFormatHolder.formatFor(dateFormat);
dateParser.set2DigitYearStart(localStartDate);
ParsePosition pos = new ParsePosition(0);
Date result = dateParser.parse(v, pos);
if (pos.getIndex() != 0) {
_LOG.debug("Date parsed using: {}", dateFormat);
return result;
}
}
_LOG.error("Can't parse data: {data:{}, formats:{}, startDate:{},tz:{}}",
dateValue, localDateFormats, localStartDate, TimeZone.getDefault());
return null;
}
My Question is:
According to document on the internet, CCT & AWST are both the GMT+8:00 time zone, why in my test it seem like that the CCT Time is GMT+9:00.

tl;dr
You have made three mistakes:
Used non-standard non-unique pseudo-time-zone 3-4 letter abbreviations
Then proceeded to incorrectly assume their meaning
Used old outmoded Java classes for date-time handling.
Instead, use proper time zone names in the format of continent/region. Study the documented meaning of those zones rather than assume/guess. Use only java.time classes for date-time work.
All these are common errors made by many programmers, as evidenced by the many Questions here on Stack Overflow.
Use proper time zone names
CST is also Central Standard Time in North America. One example of why you should never use these 3-4 letter abbreviations. They are not true time zones, not standardized, and not even unique(!). Use proper IANA time zone names. These are in the format of continent/region.
java.time
You are using old troublesome date-time classes. Avoid them.
The java.time framework is built into Java 8 and later. These classes supplant the old troublesome date-time classes such as java.util.Date, .Calendar, & java.text.SimpleDateFormat. The Joda-Time team also advises migration to java.time.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations.
Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport and further adapted to Android in ThreeTenABP.
Instant
The Instant class is a moment on the timeline in UTC (GMT) with a resolution up to nanoseconds.
Instant instant = Instant.parse ( "2016-08-02T08:12:34Z" ); // 02 Aug 2016 08:12:34
ZonedDateTime
The ZonedDateTime represents an Instant adjusted into a time zone.
I assume you meant Australian western standard time by AWST, officiall named Australia/Perth.
ZoneId zoneId_Perth = ZoneId.of ( "Australia/Perth" );
ZonedDateTime zdt_Perth = instant.atZone ( zoneId_Perth );
For China, you intended Asia/Shanghai.
ZoneId zoneId_Shanghai = ZoneId.of ( "Asia/Shanghai" );
ZonedDateTime zdt_Shanghai = zdt_Perth.withZoneSameInstant ( zoneId_Shanghai );
I am not sure what your or the old date-time classes meant by CCT. This page says it is “Cocos Islands Time”, six and a half hours ahead of UTC year-round (no Daylight Saving Time, DST). Again, this is an example of why you should never use the 3-4 letter abbreviations.
ZoneId zoneId_Cocos = ZoneId.of ( "Indian/Cocos" );
ZonedDateTime zdt_Cocos = zdt_Perth.withZoneSameInstant ( zoneId_Cocos );
You may have meant Beijing time, according to a comment. If so, know that Beijing time is covered by the Asia/Shanghai time zone according to this list in Wikipedia.
Dump to console. You can see that both Perth and Shanghai are eight hours ahead of UTC in August this year for an hour-of-day of 16 versus 8 (16:12:34 versus 08:12:34). The Cocos Islands is in between, at 14:42:34 for 6.5 hours ahead of UTC.
System.out.println ( "instant: " + instant + " | zdt_Perth: " + zdt_Perth + " | zdt_Shanghai: " + zdt_Shanghai + " | zdt_Cocos: " + zdt_Cocos );
instant: 2016-08-02T08:12:34Z | zdt_Perth: 2016-08-02T16:12:34+08:00[Australia/Perth] | zdt_Shanghai: 2016-08-02T16:12:34+08:00[Asia/Shanghai] | zdt_Cocos: 2016-08-02T14:42:34+06:30[Indian/Cocos]
DateTimeFormatter
To generate strings in formats other than the standard ISO 8601 formats shown here, use DateTimeFormatter class.
DateTimeFormatter f = DateTimeFormatter.ofLocalizedDateTime( FormatStyle.FULL );
f = f.withLocale( Locale.CHINA );
String output = zdt_Shanghai.format( f );

Display current time in 12 hour format with AM/PM

Currently the time displayed as 13:35 PM
However I want to display as 12 hour format with AM/PM, i.e 1:35 PM instead of 13:35 PM
The current code is as below
private static final int FOR_HOURS = 3600000;
private static final int FOR_MIN = 60000;
public String getTime(final Model model) {
SimpleDateFormat formatDate = new SimpleDateFormat("HH:mm a");
formatDate.setTimeZone(userContext.getUser().getTimeZone());
model.addAttribute("userCurrentTime", formatDate.format(new Date()));
final String offsetHours = String.format("%+03d:%02d", userContext.getUser().getTimeZone().getRawOffset()
/ FOR_HOURS, Math.abs(userContext.getUser().getTimeZone().getRawOffset() % FOR_HOURS / FOR_MIN));
model.addAttribute("offsetHours",
offsetHours + " " + userContext.getUser().getTimeZone().getDisplayName(Locale.ROOT));
return "systemclock";
}

Easiest way to get it by using date pattern - h:mm a, where
h - Hour in am/pm (1-12)
m - Minute in hour
a - Am/pm marker
Code snippet :
DateFormat dateFormat = new SimpleDateFormat("hh:mm a");
Read more on documentation - SimpleDateFormat java 7

Use this SimpleDateFormat formatDate = new SimpleDateFormat("hh:mm a");
Java docs for SimpleDateFormat

use "hh:mm a" instead of "HH:mm a". Here hh for 12 hour format and HH for 24 hour format.
Live Demo

SimpleDateFormat formatDate = new SimpleDateFormat("hh:mm:ss a");
h is used for AM/PM times (1-12).
H is used for 24 hour times (1-24).
a is the AM/PM marker
m is minute in hour
Note: Two h's will print a leading zero: 01:13 PM. One h will print without the leading zero: 1:13 PM.
Looks like basically everyone beat me to it already, but I digress

SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MMM-yy hh.mm.ss.S aa");
String formattedDate = dateFormat.format(new Date()).toString();
System.out.println(formattedDate);
Output:
11-Sep-13 12.25.15.375 PM

// hh:mm will print hours in 12hrs clock and mins (e.g. 02:30)
System.out.println(DateTimeFormatter.ofPattern("hh:mm").format(LocalTime.now()));
// HH:mm will print hours in 24hrs clock and mins (e.g. 14:30)
System.out.println(DateTimeFormatter.ofPattern("HH:mm").format(LocalTime.now()));
// hh:mm a will print hours in 12hrs clock, mins and AM/PM (e.g. 02:30 PM)
System.out.println(DateTimeFormatter.ofPattern("hh:mm a").format(LocalTime.now()));

Using Java 8:
LocalTime localTime = LocalTime.now();
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("hh:mm a");
System.out.println(localTime.format(dateTimeFormatter));
The output is in AM/PM Format.
Sample output: 3:00 PM

tl;dr
Let the modern java.time classes of JSR 310 automatically generate localized text, rather than hard-coding 12-hour clock and AM/PM.
LocalTime // Represent a time-of-day, without date, without time zone or offset-from-UTC.
.now( // Capture the current time-of-day as seen in a particular time zone.
ZoneId.of( "Africa/Casablanca" )
) // Returns a `LocalTime` object.
.format( // Generate text representing the value in our `LocalTime` object.
DateTimeFormatter // Class responsible for generating text representing the value of a java.time object.
.ofLocalizedTime( // Automatically localize the text being generated.
FormatStyle.SHORT // Specify how long or abbreviated the generated text should be.
) // Returns a `DateTimeFormatter` object.
.withLocale( Locale.US ) // Specifies a particular locale for the `DateTimeFormatter` rather than rely on the JVM’s current default locale. Returns another separate `DateTimeFormatter` object rather than altering the first, per immutable objects pattern.
) // Returns a `String` object.
10:31 AM
Automatically localize
Rather than insisting on 12-hour clock with AM/PM, you may want to let java.time automatically localize for you. Call DateTimeFormatter.ofLocalizedTime.
To localize, specify:
FormatStyle to determine how long or abbreviated should the string be.
Locale to determine:
The human language for translation of name of day, name of month, and such.
The cultural norms deciding issues of abbreviation, capitalization, punctuation, separators, and such.
Here we get the current time-of-day as seen in a particular time zone. Then we generate text to represent that time. We localize to French language in Canada culture, then English language in US culture.
ZoneId z = ZoneId.of( "Asia/Tokyo" ) ;
LocalTime localTime = LocalTime.now( z ) ;
// Québec
Locale locale_fr_CA = Locale.CANADA_FRENCH ; // Or `Locale.US`, and so on.
DateTimeFormatter formatterQuébec = DateTimeFormatter.ofLocalizedTime( FormatStyle.SHORT ).withLocale( locale_fr_CA ) ;
String outputQuébec = localTime.format( formatterQuébec ) ;
System.out.println( outputQuébec ) ;
// US
Locale locale_en_US = Locale.US ;
DateTimeFormatter formatterUS = DateTimeFormatter.ofLocalizedTime( FormatStyle.SHORT ).withLocale( locale_en_US ) ;
String outputUS = localTime.format( formatterUS ) ;
System.out.println( outputUS ) ;
See this code run live at IdeOne.com.
10 h 31
10:31 AM

If you want current time with AM, PM in Android use
String time = new SimpleDateFormat("hh : mm a", Locale.getDefault()).format(Calendar.getInstance().getTime());
If you want current time with am, pm
String time = new SimpleDateFormat("hh : mm a", Locale.getDefault()).format(Calendar.getInstance().getTime()).toLowerCase();
OR
From API level 26
LocalTime localTime = LocalTime.now();
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("hh:mm a");
String time = localTime.format(dateTimeFormatter);

Just replace below statement and it will work.
SimpleDateFormat formatDate = new SimpleDateFormat("hh:mm a");

SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm a");
This will display the date and time

//To get Filename + date and time
SimpleDateFormat f = new SimpleDateFormat("MMM");
SimpleDateFormat f1 = new SimpleDateFormat("dd");
SimpleDateFormat f2 = new SimpleDateFormat("a");
int h;
if(Calendar.getInstance().get(Calendar.HOUR)==0)
h=12;
else
h=Calendar.getInstance().get(Calendar.HOUR)
String filename="TestReport"+f1.format(new Date())+f.format(new Date())+h+f2.format(new Date())+".txt";
The Output Like:TestReport27Apr3PM.txt

import java.text.SimpleDateFormat;
import java.text.DateFormat;
import java.util.Date;
public class Main {
public static void main(String [] args){
try {
DateFormat parseFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm a");
String sDate = "22-01-2019 13:35 PM";
Date date = parseFormat.parse(sDate);
SimpleDateFormat displayFormat = new SimpleDateFormat("dd-MM-yyyy hh:mm a");
sDate = displayFormat.format(date);
System.out.println("The required format : " + sDate);
} catch (Exception e) {}
}
}
- Using java 8
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
public class Main
{
public static void main(String[] args)
{
String pattern = "hh:mm:ss a";
//1. LocalTime
LocalTime now = LocalTime.now();
System.out.println(now.format(DateTimeFormatter.ofPattern(pattern)));
//2. LocalDateTime
LocalDateTime nowTime = LocalDateTime.now();
System.out.println(nowTime.format(DateTimeFormatter.ofPattern(pattern)));
}
}

To put your current mobile date and time format in
Feb 9, 2018 10:36:59 PM
Date date = new Date();
String stringDate = DateFormat.getDateTimeInstance().format(date);
you can show it to your Activity, Fragment, CardView, ListView anywhere by using TextView
` TextView mDateTime;
mDateTime=findViewById(R.id.Your_TextViewId_Of_XML);
Date date = new Date();
String mStringDate = DateFormat.getDateTimeInstance().format(date);
mDateTime.setText("My Device Current Date and Time is:"+date);
`

SimpleDateFormat sdf = new SimpleDateFormat("hh:mm:ss a");
("hh:mm:ss a") >>> Here if we don't use 'a' then 24hours will be appeared. so if we want to AM/PM in your time just add this format. if any confusion please let me know.

IST to EST Time Conversion In Java

I have a Date field in Java in IST Time. I want to convert the same to EST Time and the output should be as a Date Type only. I am able to accomplish the same using the below piece of code:-
SimpleDateFormat dateTimeFormat = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
dateTimeFormat.setTimeZone(TimeZone.getTimeZone("Asia/Calcutta"));
Date date = new Date();
DateFormat timeFormat = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
timeFormat.setTimeZone(TimeZone.getTimeZone("America/New_York"));
String estTime = timeFormat.format(date);
date = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss", Locale.ENGLISH).parse(estTime);
The problem with the above piece of code is that though the date is converted in EST Time, the Time Zone is still showing as IST and not EST. The rest of the date is converted perfectly fine. Is there any way to explicitly set the time Zone To EST in the Date Field.Any help regarding this will be highly appreciated.
-Subhadeep

The Date class is time-zone agnostic. Basically, it is always based on GMT although when it is printed it uses the current system time zone to adjust it.
However, Calendar is time-zone specific. See Calendar.setTimeZone().
Consider:
Calendar cal = new GregorianCalendar();
cal.setTimeZone(TimeZone.getTimeZone("America/New_York"));
cal.setTime(new Date());

java.time
The legacy date-time API (java.util date-time types and their formatting type, SimpleDateFormat etc.) is outdated and error-prone. It is recommended to stop using it completely and switch to java.time, the modern date-time API*.
Solution using java.time, the modern API:
import java.time.Instant;
import java.time.ZoneId;
import java.time.ZonedDateTime;
public class Main {
public static void main(String[] args) {
Instant instant = Instant.now();
System.out.println(instant);
ZonedDateTime zdtIndia = instant.atZone(ZoneId.of("Asia/Calcutta"));
ZonedDateTime zdtNewYork = instant.atZone(ZoneId.of("America/New_York"));
System.out.println(zdtIndia);
System.out.println(zdtNewYork);
}
}
Output:
2021-05-19T21:08:54.241341Z
2021-05-20T02:38:54.241341+05:30[Asia/Calcutta]
2021-05-19T17:08:54.241341-04:00[America/New_York]
Instant represents an instantaneous point on the timeline. The Z in the output is the timezone designator for zero-timezone offset. It stands for Zulu and specifies the Etc/UTC timezone (which has the timezone offset of +00:00 hours).
Learn more about java.time, the modern date-time API* from Trail: Date Time.
Solution using legacy API:
The java.util.Date object is not a real date-time object like the modern date-time types; rather, it represents the number of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT (or UTC). When you print an object of java.util.Date, its toString method returns the date-time in the JVM's timezone, calculated from this milliseconds value. If you need to print the date-time in a different timezone, you will need to set the timezone to SimpleDateFormat and obtain the formatted string from it.
Demo:
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
public class Main {
public static void main(String[] args) {
Date date = new Date();
System.out.println(date);
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS[zzzzz]");
sdf.setTimeZone(TimeZone.getTimeZone("Asia/Calcutta"));
String dtIndia = sdf.format(date);
sdf.setTimeZone(TimeZone.getTimeZone("America/New_York"));
String dtNewYork = sdf.format(date);
System.out.println(dtIndia);
System.out.println(dtNewYork);
}
}
Output:
Wed May 19 22:16:08 BST 2021
2021-05-20T02:46:08.024[India Standard Time]
2021-05-19T17:16:08.024[Eastern Daylight Time]
* For any reason, if you have to stick to Java 6 or Java 7, you can use ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and How to use ThreeTenABP in Android Project.

Should you add z for time-zone pattern in your SimpleDateFormat pattern?
So, it should be DateFormat timeFormat = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss z"). I changed your code like this:
public static void main(String[] args) throws ParseException {
SimpleDateFormat dateTimeFormat = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss z");
dateTimeFormat.setTimeZone(TimeZone.getTimeZone("Asia/Calcutta"));
Date date = new Date();
System.out.println(dateTimeFormat.format(date)); // this print IST Timezone
DateFormat timeFormat = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss z");
timeFormat.setTimeZone(TimeZone.getTimeZone("America/New_York"));
String estTime = timeFormat.format(date);
date = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss z", Locale.ENGLISH).parse(estTime);
System.out.println(timeFormat.format(date)); // this print EDT Timezone currently (on March)
}
In last print statement, current date format is printed with EDT Timezone (Eastern Daylight Time). Maybe because of this.

The correct answer by John B explains that java.util.Date seems to have a time zone but does not. Its toString method applies your JVM's default time zone when generating the string representation.
That is one of many reasons to avoid java.util.Date and .Calendar classes bundled with Java. Avoid them. Instead use either Joda-Time or the java.time package built into Java 8 (inspired by Joda-Time, defined by JSR 310).
Here is some example code in Joda-Time 2.3.
String input = "01/02/2014 12:34:56";
DateTimeFormatter formatterInput = DateTimeFormat.forPattern( "MM/dd/yyyy HH:mm:ss" );
DateTimeZone timeZoneIndia = DateTimeZone.forID( "Asia/Kolkata" );
DateTime dateTimeIndia = formatterInput.withZone( timeZoneIndia ).parseDateTime( input );
DateTimeZone timeZoneNewYork = DateTimeZone.forID( "America/New_York" );
DateTime dateTimeNewYork = dateTimeIndia.withZone( timeZoneNewYork );
DateTime dateTimeUtc = dateTimeIndia.withZone( DateTimeZone.UTC );
Dump to console…
System.out.println( "input: " + input );
System.out.println( "dateTimeIndia: " + dateTimeIndia );
System.out.println( "dateTimeNewYork: " + dateTimeNewYork );
System.out.println( "dateTimeUtc: " + dateTimeUtc );
When run…
input: 01/02/2014 12:34:56
dateTimeIndia: 2014-01-02T12:34:56.000+05:30
dateTimeNewYork: 2014-01-02T02:04:56.000-05:00
dateTimeUtc: 2014-01-02T07:04:56.000Z