Monday, June 25, 2007

Jazoon 2007: Afternoon and evening

Great, I managed to do a java Black Belt attempt on Java 5 and ended up with 0/5 points. I've never even heard of that Scanner class. Think I better get started on that certification (again).


Went to a talk by Red Hat's Jan Wildeboer. Virtualization. RH now delivers a full stack with JBoss server and clustering. Most OS'es are built being able to dynamically use CPU and memory (not Windows of course).

Some keywords: VMWare invented x86 virtualization. Hypervisor, ring zero. There were performance issues (20% with heavy io, which is especially overhead intensive). Now there is something called para-virtualization with minimal overhead (1 - 5 %).

Talking about perfomance, live migration, upgrades..

Jboss clustering is still the solution for scaling up memory exploit as the JVM is not dynamically using memory or CPUs.

Virtualization offers us a lot of better perfomance, especially as more CPU's and memory are fitted onto boards.

The talk was a bit out of my league, but it is interesting to hear an alternative to Sun's Solaris/Zones we might consider. The RH guy claims he 's not allowed to present benchmarks, but that RH would win anyway.


The other guys went to see the GigaSpaces talk, so I'm tapping in on this one. I'm an old Hibernate user, and I've always wanted to dip into JDO, so that's bout the reason I'm here.

JPox Spatial, some GIS extension on the JDO standard.

Problem is mainly today that there are no tools with a DB back-end that supports GIS stuff. Or they're proprietary, etc.

JDO is a standard. JPOX is Sun's implementation. It also implements JPA.

Talks alot about different libraries from various commercial vendors that are compliant with JDO/Spatial, or the other way around.

The API for JPOX is pretty similar to Hibernate, only slighty worse (save, then get ID).

The spatial api for example gives us a query to ask whether a point is inside a polygon (or does polygons collide, etc).

All in all I think this might be a very exiting for GIS developers. There is an ISO standard on the way for doing these kind of data stores, and having a JDO API on top of these sounds like a good idea.

The speaker is doing some defence of JDO vs Hibernate, JDBC, EJB. Not new to me, I'm no happier with hibernate than I am with JPOX/JDO.

Runs with maven 1. Admittedly lacks the modularity of Spring/Hibernate.

Good idea, implementation sounds slightly immature, quite early into the market. Speaker is quite nervous, but engaged in what he's talking about.


Caught a talk on unusual use of Java to get stuff the way you usually would've done it in C. I've never been a C programmer so this talk went pretty much over my head, but it was still somewhat amusing to hear some innovative way of making your own iterators. Neil Gafter was in the seat behind me, and when he laughs it eases my mind thinking this is not stuff I have to do on my own, but can rather wait till it enters Java 7 (closures that is).


Now tapping into a talk on Java EE. Figured it was about time I try listening to something I actually know anything about. Leader of the Italian JUG presenting a year of experience with JEE 5. He's also written an Italian book on JEE 5.

The main difference is easier use with POJOs, annotations, injection, etc. Focus here is on EJB 3 and JPA. I've got to post this now but I'll post back on how it went. Probably not too many surprises in store here.