I\'ve the following code:
SimpleDateFormat format = new SimpleDateFormat(\"EEE MMM dd HH:mm:ss z yyyy\");
String s2 = \"Mon Oct 19 19:52:21 IST 2015\";
The code expression
System.out.println(format.parse(s2));
always prints your instant/moment (an object of type java.util.Date) in your system timezone which is apparently PDT. You implicitly apply the method toString()on java.util.Date. Use a dedicated formatter like SimpleDateFormat and set the timezone on this formatter to achieve the desired result.
Finally you need two formatters, one for parsing and one for printing.