Hello,
All the hibernate examples I have seen so far more or less reconstruct the their Domain Object Model (DOM) on every service call.
So the flow is
1) service call A
2) Hibernate goes to DB and constructs the needed DOM
3) DOM returns result to service A
4) service call B
5) Hibernate goes to DB and constructs again the needed DOM
6) DOM returns result to service B
...
But I would much prefer the following:
1) At the beginning of my application I construct a DOM which can answer all server requests.
2) service call A
3) DOM returns result to service A
4)service call B
5) DOM returns result to service B
....
Since in most of the examples I `ve seen the first approach seems to be mostly used....
Is there something wrong with using
the second approach together with hibernate? Or is it just not practical for a enterprise application?

Session is equivalent to a Database Connection and has an associated transaction, which is the unit of work. In an enterprise application, you typically get a connection from a connection pool, use it and release it back to the pool as soon as possible.

From a performance stand point, you should probably start looking at hibernate's secondary level cache support rather than share connections/sessions.