7). Which Hibernate object wraps the JDBC Connection?
The Session interface wraps a JDBC Connection. This interface is a
single threaded object which represents a single unit of work with application
and persistent database. It’s retrieved by the SessionFactory’s openSession()
method
8). Is the Session Factory Thread safe?
Yes: that is many threads can access it cuncurrentely and request for
sessions. It holds cached data that has been read in one unit of work and may
be reused in a future unit of work. Good practice is to create it when the
application is initialized.
9). How can you start a JTA transaction from a Servlet deployed on
JBoss?
JBoss registers in the JNDI tree a JTA UserTransaction Object which can be
user to manage a distributed transaction.
10). What if you need to span your transaction across multiple Servlet
invocations?
You can’t with a Servlet. A JTA transaction must start and finish within
a single invocation (of the service() method). You should consider using a
Stateful SB. In a SFSB with a JTA transaction, the association between the bean
instance and the transaction is retained across multiple client calls.
