Does Java's `java.sql.Timestamp` Storage Depend on the Time Zone?

Is java.sql.Timestamp's Storage Influenced by Time Zone?

In JDBC, the setTimestamp() method's behavior with java.sql.Timestamp may vary based on the driver implementation.

Driver's Behavior:

Most drivers adhere to the rules outlined in the javadoc for setTimestamp(int parameterIndex, Timestamp x, Calendar cal). If no Calendar object is provided, the driver typically uses the time zone of the virtual machine running the application.

Timestamp Storage in the Database:

When using setTimestamp(int parameterIndex, Timestamp x) without specifying a Calendar, the driver converts the timestamp to the VM's time zone before storing it in the database. If the database column lacks time zone information, this conversion may result in the loss of time zone data.

Example:

Consider a local time zone of GMT 2 and a UTC timestamp of "2012-12-25 10:00:00 UTC." After storage in the database, the timestamp appears as "2012-12-25 12:00:00" (GMT 2). If retrieved by an application in GMT 0, the timestamp would be interpreted as "2012-12-25 12:00:00 UTC."

Storing Timestamps in Specific Time Zones:

To store timestamps in a specific time zone, use setTimestamp(int parameterIndex, Timestamp x, Calendar cal) with the desired Calendar instance (e.g., Calendar.getInstance(TimeZone.getTimeZone("GMT")) for GMT).

Timestamp Retrieval:

Similarly, when retrieving timestamps, ensure that you use the same time zone as when storing them.

Using java.time.LocalDateTime with JDBC 4.2 :

In JDBC 4.2 compliant drivers, you can use java.time.LocalDateTime (and java.time.LocalTime) with TIMESTAMP and TIME types through the get/set/updateObject methods. These classes represent time without time zones.

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