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How do i get a date object for a specific timezone from a string date in Java? [duplicate]

This question already has answers here:
Convert date string (EST) to Java Date (UTC)
(2 answers)
Convert Calender to Date according to timezone [duplicate]
(1 answer)
Closed 3 days ago.
I have a string with value "25/12/2021" and I want to convert this string into a date format which has a New York timezone.
I am new to Java dates
I tried the below:
SimpleDateFormat zdate = new SimpleDateFormat("dd/MM/yyyy");
zdate.setTimeZone(TimeZone.getTimeZone("America/New_York"));
Date zdate2 = zdate.parse("25/12/2021")
but the zdate2 object has the date in my local timezone rather than the New_York timezone.
What am I doing wrong here?

If you are not forced to use java.util.Date, which itself does not have any zone, you could have your requirement met by implementing with java.time:
You just have to
parse it to a LocalDate, a class only having year, month of year and day of month
append a time of day
append the zone
Here's an example…
public static void main(String[] args) throws ParseException {
// example input
String input = "25/12/2021";
// create a pattern handler for parsing
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("dd/MM/uuuu");
// create the zone
ZoneId americaNewYork = ZoneId.of("America/New_York");
// parse the String to a LocalDate, then add time of day and zone
ZonedDateTime result = LocalDate.parse(input, dtf)
.atStartOfDay(americaNewYork);
System.out.println(result);
}
Output:
2021-12-25T00:00-05:00[America/New_York]

Small protest about parse() on time objects, the following is what it really takes to assure creation from String information that parse() methods continually reject !!!
bash-5.1$ javac ZoneParse.java
Note: ZoneParse.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
bash-5.1$ java ZoneParse
24 Dec 2021 13:00:00 GMT
bash-5.1$
It will be something alike the following if safe...
import java.time.*;
public class ZoneParse{
public ZoneParse(){
String[] dt = ("25/12/2021").split("/");
ZonedDateTime ztm = (LocalDate.of(new Integer(dt[2]).intValue(),new Integer(dt[1]).intValue(),new Integer(dt[0]).intValue())).atStartOfDay(ZoneId.systemDefault());
System.out.println((java.util.Date.from( (ztm.withZoneSameInstant((ZoneId)ZoneId.of("America/New_York")).toInstant()))).toGMTString());
}//enconstr
public static void main(String[] args){
new ZoneParse();
}//enmain
}//enclss
NOTE withZoneSameInstant() changes both the time and the zone.
withZoneSameLocal() only retags the time as belonging as another time zone
The updated time library since around java 8 is quicker
This following link is a library with some time assistance under construction avoids parse() as much as possible including a pair of methods of String fill in arguments to create a timedate.
https://drive.google.com/file/d/1gjHmdC-BW0Q2vXiQYmp1rzPU497sybNy/view?usp=share_link
The below erroneous code is because parse() is probably one of the WORST explained methods in the docs, it generally requires a few different pages each of different sections to get any explanation of how to use it.
ZonedDateTime ztm = ZonedDateTime.parse("25/12/2021");
Instant it = (ztm.withZoneSameInstant((ZoneId)ZoneId.of("America/New_York"))).toInstant();
java.util.Date date = java.util.Date.from(it);

SimpleDateFormat zdate = new SimpleDateFormat("dd/MM/yyyy");
zdate.setTimeZone(TimeZone.getTimeZone("America/New_York"));
Date zdate2 = zdate.parse("25/12/2021")
Remember the four 'y' letters in format

How to convert 2022-08-16T06:25:00.000 to HH:mm

I'm trying to convert date from API "2022-08-16T06:25:00.000" to HH:mm (6:25) but getting DateTimeParseException.
My code: ZonedDateTime.parse(it.time[0], DateTimeFormatter.ofPattern("HH:mm"))
"time": [
"2022-08-16T06:25:00.000",
"2022-08-16T07:40:00.000"
],

String dateTimeStr = "2022-08-16T06:25:00.000";
LocalDateTime dateTime = LocalDateTime.parse(dateTimeStr);
DateTimeFormatter fmt = DateTimeFormatter.ofPattern("HH:mm");
String time = dateTime.format(fmt);
System.out.println(time);
or, if you want to use the time as an instance of LocalTime, you can get it by dateTime.toLocalTime()

You don't need to define any DateTimeFormatter in this situation.
use a LocalDateTime because the input String does not hold any information about the zone
don't use a DateTimeFormatter for parsing that only parses hour of day and minutes of hour, the String to be parsed just contains more information
Here's an example without any DateTimeFormatter explicitly defined (but it will use default ones for parsing, at least):
public static void main(String[] args) {
// example input
String fromApi = "2022-08-16T06:25:00.000";
// parse it to a LocalDateTime because there's no zone in the String
LocalDateTime localDateTime = LocalDateTime.parse(fromApi);
// extract the time-of-day part
LocalTime localTime = localDateTime.toLocalTime();
// and print its toString() implicitly
System.out.println(localTime);
}
Output: 06:25
The above code will produce output of the pattern HH:mm, which will have leading zeros at hours of day to always have a two-digit representation.
If you insist on single-digit hours of day, you will have to prepare a DateTimeFormatter, like in this alternative example:
public static void main(String[] args) {
// example input
String fromApi = "2022-08-16T06:25:00.000";
// parse it to a LocalDateTime because there's no zone in the String
LocalDateTime localDateTime = LocalDateTime.parse(fromApi);
// extract the time-of-day part
LocalTime localTime = localDateTime.toLocalTime();
// prepare a DateTimeFormatter that formats single-digit hours of day
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("H:mm");
// print the LocalTime formatted by that DateTimeFormatter
System.out.println(localTime.format(dtf));
}
Output this time: 6:25

The other answers use Java. Since you've added a [kotlin] tag, here is a Kotlin-based answer for the sake of completeness. In order to make it different to the Java answers, I'm using kotlinx.datetime, which is still at the experimental stage at version 0.4.0.
import kotlinx.datetime.LocalDateTime
fun main() {
println(LocalDateTime.parse("2022-08-16T06:25:00.000").time) // prints "06:25"
// If you want "6:25" you can format it yourself:
println(with(LocalDateTime.parse("2022-08-16T06:25:00.000")) {
"$hour:$minute"
})
}

How about different approach
String dateTimeStr = "2022-08-16T06:25:00.000";
Matcher m=Pattern.of("T(\\d{2}:\\d{2}):").matcher(dateTimeStr);
m.find();
System.out.println(m.group(1);; //should print 06:25

And yet another "alternative" answer. It relies on the fact that in an ISO-compliant date-time format, the time starts in the 11th position.
private static final int ISO_TIME_POS = 11;
....
String dateTimeStr = "2022-08-16T06:25:00.000";
String timeStr = dateTimeStr.substring(ISO_TIME_POS, ISO_TIME_POS + 5);
System.out.println(timeStr); // prints "06:25"

java.text.ParseException: Unparseable date Error on using Clock.systemUTC() [duplicate]

This question already has answers here:
how to parse OffsetTime for format HHmmssZ
(2 answers)
Closed 1 year ago.
I am getting an parse error while parsing a date
java.text.ParseException: Unparseable date: "2021-06-17T05:49:41.174Z"
Unparseable date: "2021-06-17T05:49:41.174Z"
my code looks like this
private static String generateAndValidate(int count) {
Clock clock = Clock.systemUTC();
String clockTime=clock.instant().toString();
String result=clockTime;
SimpleDateFormat output = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ",Locale.ENGLISH);
try {
output.parse(clockTime);
} catch (ParseException e) {
System.out.println("process date parse error. Going for retry.");
}
return result;
}
Also tried hard coding the value here
SimpleDateFormat output = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ",Locale.ENGLISH);
try {
output.parse("2021-06-17T05:49:41.174Z");
} catch (ParseException e) {
System.out.println("process date parse error. Going for retry.");
}
What could be the problem?

EDIT: The reason for the failing of your code is in the answer given by #GS3!
My answer provides alternatives that are generally considered mroe up-to-date:
I would not recommend to use a java.text.SimpleDateFormat here because you are involving a very old and practically outdated API while you are receiving the time by the modern API utilizing a java.time.Clock.
A good move would be to use java.time.format.DateTimeFormatters for parsing, but I think you could even skip the clock and use OffsetDateTime.now(ZoneOffset.UTC).
However, this code definitely parses the String produced by your first lines:
public static void main(String[] args) {
// your first two lines
Clock clock = Clock.systemUTC();
String clockTime = clock.instant().toString();
// a hint to the problem
System.out.println(clockTime + " <--- 6 fractions of second");
// how to parse a String like that in plain java.time
OffsetDateTime odt = OffsetDateTime.parse(clockTime);
System.out.println(odt.format(
DateTimeFormatter.ISO_OFFSET_DATE_TIME
)
);
}
The output of that will look like the following (obviously having different values):
2021-06-17T06:34:55.490370Z <--- 6 fractions of second
2021-06-17T06:34:55.49037Z
The output that uses a DateTimeFormatter.ISO_OFFSET_DATE_TIME is just one option, you can still define your own pattern using a DateTimeFormatter.ofPattern(yourPatternString), a DateTimeFormatterBuilder in order to handle optional parts or one of the other built-in formatters.
If you just want to get the current moment and store it in a some datetime class, you can use the now() method the datetime classes in java.time have:
OffsetDateTime now = OffsetDateTime.now(ZoneOffset.UTC);
looks suitable here, but there's a ZonedDateTime, too.
Just have a look at java.time...

In SimpleDateFormat, Z represents a restricted subset of the RFC-822 time zone syntax. Instant::toString() provides a timestamp in the ISO-8601 format. You can fix this by using X instead of Z.
SimpleDateFormat output = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSX",Locale.ENGLISH);

Convert a string into iso date format

So I am trying to convert a string into an iso format for the date.
This is the string that I am trying to convert "2016-07-05 02:14:35.0"
I would like to have it in this format the iso 8601
"2016-07-05T02:14:35.0"
I have this so far
DateTimeFormatter format = DateTimeFormat.forPattern("YYYY-MM-DDTHH:mm:sszzz");
new LocalDate();
LocalDate newDate = LocalDate.parse(created,format);
created = newDate.toString();
But it is giving me this exception
ERROR: Illegal pattern component: T; nested exception is java.lang.IllegalArgumentException: Illegal pattern component: T
I followed the examples and I don't know what I am doing wrong here.
Any help would be appreciated.

Firstly, that value is a LocalDateTime, not a LocalDate. If you want to get a date out in the end, I'd convert it to a LocalDateTime first, then take the date part of that.
When performing date formatting and parsing, always read the documentation really carefully. It looks like you're using Joda Time (due to using forPattern; if you can move to Java 8 that would be beneficial). That means you should be reading the DateTimeFormat docs.
Current problems with your pattern:
You're using 'D' instead of 'd'; that means day-of-year
You've specified 'T' without quoting it, and it isn't in the pattern anyway
You've ignored the fraction-of-second part of your value
You've specified 'zz' when there's no time zone indicator in the value.
Here's a working example:
import org.joda.time.*;
import org.joda.time.format.*;
public class Test {
public static void main(String[] args) {
String text = "2016-07-05 02:14:35.0";
DateTimeFormatter format = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss.S");
LocalDateTime localDateTime = LocalDateTime.parse(text, format);
System.out.println(localDateTime);
}
}
If you actually want to parse values with T in the middle, you'd use a pattern of "yyyy-MM-dd'T'HH:mm:ss.S" - note how then the T is quoted so it's treated literally instead of as a format specifier.
Note that this is just parsing. It's not "converting a string into ISO date format" - it's converting a string into a LocalDateTime. If you then want to format that value in an ISO format, you need to be using DateTimeFormatter.print, with an appropriate format. For example, you might want to convert to a format of yyyy-MM-dd'T'HH:mm:ss.S':
import org.joda.time.*;
import org.joda.time.format.*;
public class Test {
public static void main(String[] args) {
String text = "2016-07-05 02:14:35.0";
DateTimeFormatter parser = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss.S");
LocalDateTime localDateTime = LocalDateTime.parse(text, parser);
DateTimeFormatter printer = DateTimeFormat.forPattern("yyyy-MM-dd'T'HH:mm:ss.S");
String formatted = printer.print(localDateTime);
System.out.println(formatted); // Output 2016-07-05T02:14:35.0
}
}
The code above will only handle a single digit fraction-of-second. You could parse using .SSS instead of .S, but you really need to work out what you want the output to be in different cases (e.g. for 100 milliseconds, do you want .1 or .100?).

You have some errors in your code:
The pattern should be 'yyyy-MM-dd HH:mm:ss.SSS'. Be aware of upper-
and lowercase.
Use LocalDateTime to get date and time. LocalDate only holds the date.
The corrected code:
String created = "2016-07-05 02:14:35.000";
DateTimeFormatter format = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS");
LocalDateTime newDate = LocalDateTime.parse(created,format);
created = newDate.toString();
System.out.println(created);

Use the following format to convert
String format = "yyyy-mm-dd hh:mm:ss"
You are using the wrong format to convert. Using T is only to separate the date from time.
Use the format like this
String = "yyyy-MM-dd'T'HH:mm:ss"

How can I convert a timestamp from yyyy-MM-ddThh:mm:ss:SSSZ format to MM/dd/yyyy hh:mm:ss.SSS format? From ISO8601 to UTC

I want to convert the timestamp 2011-03-10T11:54:30.207Z to 10/03/2011 11:54:30.207. How can I do this? I want to convert ISO8601 format to UTC and then that UTC should be location aware. Please help
String str_date="2011-03-10T11:54:30.207Z";
DateFormat formatter ;
Date date ;
formatter = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss.SSS");
date = (Date)formatter.parse(str_date);
System.out.println("output: " +date );
Exception :java.text.ParseException: Unparseable date: "2011-03-10T11:54:30.207Z"

Firstly, you need to be aware that UTC isn't a format, it's a time zone, effectively. So "converting from ISO8601 to UTC" doesn't really make sense as a concept.
However, here's a sample program using Joda Time which parses the text into a DateTime and then formats it. I've guessed at a format you may want to use - you haven't really provided enough information about what you're trying to do to say more than that. You may also want to consider time zones... do you want to display the local time at the specified instant? If so, you'll need to work out the user's time zone and convert appropriately.
import org.joda.time.*;
import org.joda.time.format.*;
public class Test {
public static void main(String[] args) {
String text = "2011-03-10T11:54:30.207Z";
DateTimeFormatter parser = ISODateTimeFormat.dateTime();
DateTime dt = parser.parseDateTime(text);
DateTimeFormatter formatter = DateTimeFormat.mediumDateTime();
System.out.println(formatter.print(dt));
}
}

Yes. you can use SimpleDateFormat like this.
SimpleDateFormat formatter, FORMATTER;
formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
String oldDate = "2011-03-10T11:54:30.207Z";
Date date = formatter.parse(oldDate.substring(0, 24));
FORMATTER = new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss.SSS");
System.out.println("OldDate-->"+oldDate);
System.out.println("NewDate-->"+FORMATTER.format(date));
Output
OldDate-->2011-03-10T11:54:30.207Z
NewDate-->10-Mar-2011 11:54:30.207

Enter the original date into a Date object and then print out the result with a DateFormat. You may have to split up the string into smaller pieces to create the initial Date object, if the automatic parse method does not accept your format.
Pseudocode:
Date inputDate = convertYourInputIntoADateInWhateverWayYouPrefer(inputString);
DateFormat outputFormat = new SimpleDateFormat("MM/dd/yyyy hh:mm:ss.SSS");
String outputString = outputFormat.format(inputDate);

You might want to have a look at joda time, which is a little easier to use than the java native date tools, and provides many common date patterns pre-built.
In response to comments, more detail:
To do this using Joda time, you need two DateTimeFormatters - one for your input format to parse your input and one for your output format to print your output. Your input format is an ISO standard format, so Joda time's ISODateTimeFormat class has a static method with a parser for it already: dateHourMinuteSecondMillis. Your output format isn't one they have a pre-built formatter for, so you'll have to make one yourself using DateTimeFormat. I think DateTimeFormat.forPattern("mm/dd/yyyy kk:mm:ss.SSS"); should do the trick. Once you have your two formatters, call the parseDateTime() method on the input format and the print method on the output format to get your result, as a string.
Putting it together should look something like this (warning, untested):
DateTimeFormatter input = ISODateTimeFormat.dateHourMinuteSecondMillis();
DateTimeFormatter output = DateTimeFormat.forPattern("mm/dd/yyyy kk:mm:ss.SSS");
String outputFormat = output.print( input.parseDate(inputFormat) );

Hope this Helps:
public String getSystemTimeInBelowFormat() {
String timestamp = new SimpleDateFormat("yyyy-mm-dd 'T' HH:MM:SS.mmm-HH:SS").format(new Date());
return timestamp;
}

Use DateFormat. (Sorry, but the brevity of the question does not warrant a longer or more detailed answer.)