Actually this is not a duplicate question. And this how i solve my problem after several times :
int offset = DateTimeZone.forID("anytimezone").getOffset(new DateTime());
This is the way to get offset from desired timezone.
Let's return to our code, we were getting timestamp from a result set of query, and using it with timezone to create our datetime.
DateTime dt = new DateTime(rs.getTimestamp("anytimestampcolumn"),
DateTimeZone.forID("anytimezone"));
Now we will add our offset to the datetime, and get the timestamp from it.
dt = dt.plusMillis(offset);
Timestamp ts = new Timestamp(dt.getMillis());
May be this is not the actual way to get it, but it solves my case. I hope it helps anyone who is stuck here.