Java SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'") gives timezone as IST

Question

You haven't set the timezone only added a Z to the end of the date/time, so it will look like a GMT date/time but this doesn't change the value.

Set the timezone to GMT and it will be correct.

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));

'T' and 'Z' are considered here as constants. You need to pass Z without the quotes. Moreover you need to specify the timezone in the input string.

Example : 2013-09-29T18:46:19-0700 And the format as "yyyy-MM-dd'T'HH:mm:ssZ"

From ISO 8601 String to Java Date Object

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
sdf.parse("2013-09-29T18:46:19Z"); //prints-> Mon Sep 30 02:46:19 CST 2013

if you don't set TimeZone.getTimeZone("GMT") then it will output Sun Sep 29 18:46:19 CST 2013

From Java Date Object to ISO 8601 String

And to convert Dateobject to ISO 8601 Standard (yyyy-MM-dd'T'HH:mm:ss'Z') use following code

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US);
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));           
System.out.println(sdf.format(new Date())); //-prints-> 2015-01-22T03:23:26Z

Also note that without ' ' at Z yyyy-MM-dd'T'HH:mm:ssZ prints 2015-01-22T03:41:02+0000

IF you want to handle 'standard' JSON representation of the Date then better to use this pattern: "yyyy-MM-dd'T'HH:mm:ssX".

Notice the X on the end. It will handle timezones in ISO 8601 standard, and ISO 8601 is exactly what produces this statement in Javascript new Date().toJSON()

Comparing to other answers it has some benefits:

1. You don't need to require your clients to send date in GMT
2. You don't need to explicitly convert your Date object to GMT using this: sdf.setTimeZone(TimeZone.getTimeZone("GMT"));