Question

I have a table which stores both unix time and the equivalent time stamp.

CREATE TABLE tbl_time
(
    time_unix BIGINT,
    time_timestamp TIMESTAMP WITHOUT TIME ZONE
);

The database is in PostgreSQL. database has been configured with Asia/Tehran time zone.
for example:

1333436817, 2012-04-03 11:36:57

When I convert the unix time into string format in python with:

datetime.datetime.fromtimestamp(1333436817)

it gives me: datetime.datetime(2012, 4, 3, 11, 36, 57) which is correct and equal to database. But when I do this conversion with java using:

Calendar c = Calendar.getInstance(TimeZone.getTimeZone("Asia/Tehran"));
c.setTimeInMillis(1333436817 * 1000);
System.out.println(c.getTime());

It gives: Sat Jan 24 06:12:35 IRST 1970. The system itself is running under Asia/Tehran time zone. I’m using PostgreSQL 8.4.11 on Debian 6.0.5 with python 3.1 and openjdk 6. Can anyone help?

Answer 1

The result of 1333436817 * 1000 is too big for an integer so it overflows. Java will not promote the type for you automatically in this case.

Try that:

    c.setTimeInMillis(1333436817 * 1000L);

Notice the L that force your calculation to use long integer.