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I am trying to convert GMT to IST. 

  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSSSSS");
  Date c= sdf.parse("2017-03-31T10:38:14.4723017Z");

  Date date = new Date();
  DateFormat istFormat = new SimpleDateFormat();
  DateFormat gmtFormat = new SimpleDateFormat();
  TimeZone gmtTime = TimeZone.getTimeZone("GMT");
  TimeZone istTime = TimeZone.getTimeZone("IST");

  istFormat.setTimeZone(gmtTime);
  gmtFormat.setTimeZone(istTime);
  System.out.println("GMT Time: " + istFormat.format(c));
  System.out.println("IST Time: " + gmtFormat.format(c));

My output is 

GMT Time: 31/3/17 6:26 AM
IST Time: 31/3/17 11:56 AM

But my actual output should be 

GMT Time: 31/3/17 5:08 AM
IST Time: 31/3/17 10:38 AM

What is wrong with my code?

kushi
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3 Answers3

7

Milliseconds (SSS) can only be three digits. On more than that, the date rolls over - e.g. 10:38:14.1000 becomes 10:38:15.000. Add a couple of million milliseconds... and you get the behaviour that you're seeing now.

Try this.

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS");
Date c = sdf.parse("2017-03-31T10:38:14.472Z");

System.out.println(c);

DateFormat istFormat = new SimpleDateFormat();
DateFormat gmtFormat = new SimpleDateFormat();
TimeZone gmtTime = TimeZone.getTimeZone("GMT");
TimeZone istTime = TimeZone.getTimeZone("IST");

istFormat.setTimeZone(gmtTime);
gmtFormat.setTimeZone(istTime);
System.out.println("GMT Time: " + istFormat.format(c));
System.out.println("IST Time: " + gmtFormat.format(c));
Riaan Nel
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  • In this case 4723017 comes out to 1 hour and 18 minutes. This matches the offset seen between the actual and expected. – ProgrammersBlock May 16 '17 at 12:08
  • I am getting response with 7digits of ms. Is there any way to change it programmatically? – kushi May 16 '17 at 12:14
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    It's probably not in milliseconds, it might be in nanoseconds. Do a substring to cut off the extra numbers if they are not necessary. – ProgrammersBlock May 16 '17 at 12:15
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    Parse the first 3 digits. This is probably being repersented as an ISO 8601:2004 date where "fractions of Seconds" can be specified. See: http://stackoverflow.com/questions/25842840/representing-fraction-of-second-with-iso-86012004. Java thinks they are milliseconds. I ran into this problem before when passing dates between Java and .NET. – Allan May 16 '17 at 12:16
0

Have you tried changing the format to "yyyy-MM-dd'T'HH:mm:ss.sssssssZ"?

Also, when you type Z in your Date object, you should write the time zone designator, for example, "2017-03-31T10:38:14.4723017+01:00".

Urko Pineda
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    's' is seconds in a minute, so that will still result in strange behaviour. The original issue comes down to the representation of the date itself - milliseconds cannot be more than three digits. – Riaan Nel May 16 '17 at 12:09
0

Try use this format "yyyy-MM-dd'T'HH:mm:ss.SSSSSSSZ"

Mikhail Yaskou
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