I have multiple threads running, each one is creating a transaction over a single session..


According to the API doc, "it is intended that there be at most one uncommitted Transaction associated with a particular Session at any time"

Is there no way to run concurrent transactions in hibernate over a single session?



I am using Hibernate 3.2

If each thread is getting its own individual session from the sessionfactory then there are no issues. If you have multiple threads accessing the same session instance then this is not thread safe. In general nested transactions are not supported by database vendors. The JTA spec gets around it by suspending a transaction (throught the TransactionManager interface) to allow another Tx to be used. Hibernate can emulate this in JDBC Tx mode.

I am confused with the notion of nested transactions... transactions started in multiple threads are supposed to run parallely and individually right?

If i start transaction in multiple threads over a single session, cant i achieve parallelism? will the transactions run sequentially?