Difference in date calculation Java SimpleDateFormat

I have a requirement to parse the date into milliseconds. Here is how I am doing it.

 private static final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");

      public void setTime(String date) {
      try {
            sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
            this.time = sdf.parse(date).getTime();
        } catch (ParseException e) {
                e.printStackTrace();
        }

Here is the problem in my server.

For example, for the given input date "2015-06-20T01:57:13Z", I get output value as 1592618233000 ms, however, the expected value should be 1434765433000.

Analyzing the issue I found that difference of 157852800000 ms which when converted gives to "Thu Jan 01 1975 05:30:00 GMT+0530 (IST)" Date.

I see that 157852800000 ms is getting added to few of the dates in my server. There is no code issue here. I am using the code as shown above. When I run the same in my local machine it is working absolutely fine. Also, this scenario in my server do not occur all the times.

Please advise on this.