JavaPolis day 2
Juergen Hoeller and Rod Johnson gave a good introduction to Spring.
I am a Spring newbie, so this session was interesting for me, although quite for beginners. I definitely have to study deeper the matter.
Especially seems to me that Spring (but I guess also other lightweight containers such as HiveMind) gathers good ol' ideas into a comfortable place one can call "framework".
WebWork1 uses *Aware interfaces (not necessarily introduced before Spring, but I think independently), Jetty uses XML configuration files (same as above) and so on.
Spring ties this and much much more together and gives you a comfortable place to put together your components.
Hibernate in Action
Gavin King and Christian Bauer gave an introduction to Hibernate2 with some glance to Hibernate3 and to EJB3.
Especially these glances make unmissable their next presentation focused on Hibernate3, since with use of annotations the XML mapping files become history and the entity class ridiculously simple (and similarly will EJB3 entity classes).
Among many new features, Hibernate3 will have filters (never had the problem of filtering the resultset basing - for example - on some property of the user that logged in ?), a complete event model for relevant actions done to the object graph, JMX performance statistics on queries (how many time each one, how long it took, etc), and much more.
Christian's tip of the session: check out what the "any type mapping" does in Hibernate, sometimes can be useful.
Christian's warning of the session: always use a DB with referential constraints. Remove referential constraints, but then be prepared to see this sentence written on the next door you want to open: "Lasciate ogni speranza, o voi ch'entrate".
Gavin's statement of the session was that JDO vendors should provide a path of migration from JDO to EJB3 since that will be the future.