The first session I attended on day 2 was called "Architecting for Performance and Scalability", where representatives from Terracotta, (Oracle) Coherence, GigaSpaces, etc (and eBay) came together to talk about the different approaches to building scalable systems. It was surprisingly civilised and it was interesting to compare and contrast each vendor's approach to dealing with the scalability problem. Here are my takeaway points from this session :

• On average, the audience thought that they could squeeze 2x performance out of their existing systems if given a couple of weeks to tune it. If you need any more, you need to architect/design with that in mind. In other words, you need to design in scalability from the start.
• Ultimately, many of these decisions are economic in nature. It's okay for a business to demand ultra high scalability, but they will pay for it in terms of hard cash and time to market. It's all about trade-offs.
• Continuous performance testing is an important thing to do if you're building systems that are performance critical. The implication of this, of course, is that you *have* something to test, which for me points to an iterative development approach and an executable reference architecture as early as possible.

The next session I attended was called "A Tale of Two Systems", which basically presented a picture of what happens when you do and don't design your software. Anybody experienced in software development won't have seen any surprises here, but it was nice to see the good and the bad contrasted in a very down-to-earth way. There was a definite agile spin of all of this; with talk of flat team structures and a distribution of the design responsibility throughout the team. In fact, Pete stated that "he'd never worked on a project that needed an architect". While these approaches work well for small and/or simple projects, I'm still of the opinion that *some* architecture needs to be performed up-front and that somebody needs to take ultimate responsibility.

Following the talk about software design was a talk about user interface design, entitled "User Interfaces: Meeting the challenge of simplicity". This session looked at the art of designing user interfaces so that they appear simple to the user, and that how making even the smallest of changes can have a huge impact. One of the most interesting parts of this session was that it almost completely paralleled the session that preceded it; in terms of talking about agile development, feedback, simplicity, you aren't going to need it (YAGNI), etc.

The final session I attended was Neil Gafter's look at the new features that are being considered for Java 7 and beyond. I've not been following this too closely and it was interesting to catch up with it all. One of the things that struck me most was that the Java platform JSR hasn't even been started yet and that Sun don't seem to have enough resources to do everything that they want to (apparently JavaFX is more important?). I was under the impression that major releases of the platform were going to be on an 18 month cycle, but clearly that's not going to happen. I also don't necessarily understand where/how the open source stuff fits into all of this. There are some nice smaller features being considered for Java 7 (multi exception catching, easy exception rethrowing, the ability to switch on Strings, etc) but part of me thinks that maybe the bigger language changes (e.g. closures) shouldn't be implemented. Perhaps it might be better to stop making big changes to the Java language and start putting more effort into something else (e.g. Scala, Groovy, etc).

All in all, another great day at the conference and some interesting discussion in the bar afterwards.

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Posted by Simon Brown on 14 March 2008 08:46:00 GMT #