Re: JPA in practice
Lew wrote:
Learning how to do this, I was running Glassfish 3 with a Postgres
back end, but my 4 GB RAM server box's power supply just gave up the
ghost. Turns out the combination of GF and PG with NetBeans was too
much for my poor single-core 64-bit workstation with only 1 GB RAM.
Then I tried the non-injective approach with Tomcat, Postgres and
NetBeans. Turns out that runs just great on the workstation.
That triggered a major "Hmmm." I may be on to a way to develop,
deliver and deploy full-blown custom apps very quickly with very low
administrative and hardware overhead.
Tom Anderson wrote:
I'm surprised GF took *so* much extra memory (and CPU?). What's it doing?
Are there any lightweight app servers that wouldn't be a big overhead
over Tomcat (or perhaps even better, Jetty)?
In part the answer depends on how much app server you need. Tomcat already is
an app server for web apps and web services. Arved's suggestion of Seam
<http://www.jboss.com/products/seam/>
seems promising.
Do you need EJBs? Tomcat with Apache OpenEJB might do the trick. Seam does
that, too. One day I'll test to find out, if I can figure out why I ever need
EJBs.
Do you just need dependency injection? Maybe Spring is enough (or too much -
I'm still deciding).
Do you need message queues? BPEL? Integrated JNDI? Multiple cooperating
apps or quasi-independent components? Common services for multiple enterprise
applications? Clustering or other scalability strategies?
My untested hypothesis is that there's a threshold of system complexity or
performance where the overhead of a full-blown app server like JBoss or
Glassfish is less than the difficulty of managing or scaling piecemeal solutions.
If nothing else, there's the fact that the job market requires practitioner
skill in all of that, so it behooves me to buy a new power supply for my
multi-core PC and keep practicing with full-bore Java EE.
--
Lew