donderdag 13 november 2008

JFall 2008

Today I went to the Jfall. First a big thanks to the NLJUG for allowing me to take 35 of my students for free. I suspect a number of them skipped it due to illness, oversleeping and whatever reasons. They don’t know what they missed.

I started off with a talk by Marco Mulder from Xebia. He talked about a large project they have done for Prorail, using agile software development (Scrum) and a distributed development team (Netherlands and India). This of course involved some challenges which they solved nicely. I also learned a bit more about Scrum to complement what I know about eXtreme Programming.

Then there was a talk about Constraint Satisfaction Problem solving with Java by Nicolas van Hanxleden (Iprofs). Constraint Satisfaction Problems (CSP) are all about scheduling and optimisation and are typically unsolvable by a brute force approach. Since I studied these kinds of problems when I was in university, I was interested to hear if there is anything new. The first 75% of the presentation was largely familiar, although he did a good job explaining it. Nicolas then introduced the open source tool Cream which can be used to model and solve CSP’s. He gave a good demo in which he applied Cream to solving the N-queen problem.

Lunchtime! The handing out was a bit annoying just like at the JSpring. After getting up pretty early you don’t want to stand in a long line which is not moving. I’d like to challenge the NLJUG to improve the logistics of the lunch. That shouldn’t be too difficult. :-)

The keynote after lunch by Reginald Hutcherson (Sun) was amusing but not really informative. (Dude, simplify your slides). Two other Sun guys showed some fun demo’s of Java FX but nothing really challenging. The thing I might remember most is the throwing of the T-shirts into the crowd. But ok, maybe having some fun was all they wanted to achieve.

Immediately after that there was a talk about Lean Software Development by Marc Evers and Rob Westgeest. This also fit in nicely in my objective to complete my knowledge about agile software development methodologies. But I must note that the speakers emphasized that Lean is not a methodology but a set of principles, a certain mindset. What was new for me was the notion of measuring the worktime for a specific development cycle and comparing it to the total time before the product available to the business. In the example given they calculated the “efficiency” as 6%, all the other time going wasted to errors and (mainly) waiting. One of the key principles of Lean is to eliminate this “waste”. To do this they use other techniques from the production industry like applying “pull” instead of “push”. A lot of these ideas stem from Toyota car manufacturing. This talk was ok.

This time I decided to skip the last two talks and try my luck at a hands-on workshop on unittesting. This didn’t really work out however. After finally getting my laptop from the wardrobe and some installation trouble I was lagging too much behind on the assignment which I would have found quite challenging even if I started right from the beginning. The other participants were clearly having a good time, so no problem.

See you next year at the Jspring!

2 opmerkingen:

peter zei


I came in late, and only attended the latest presentation about Java FX. Before that I walked around the stands, which was fun and informative. Also ate a lot of ice cream.

The Java FX presentation started immediately about technical aspects like binding objects, without telling exactly what Java FX is and what it can be used for.

After that some demo's were given. For example a window with a videoplayer embedded, which was rotating. And a small game. Looked slick, and reminded me of flash.

The presentator went quick through the sheets and had good humour.


Peter V

Robin zei

Heey mr. Baljé,

Nice blog you have here! Why didn't you mention it before? *searches for email notifications*

Anyways, most of the presentations on JFall were quite ok, but the facilities could have been better indeed.

We had to wait for almost half an hour for our foodbox. Wouldn't be too bad if the food was edible, but when we finally arrived at the bar, only vegetarian boxes were available!

Besides that, we had lots of fun visiting various presentations. The "Cool new APIs" presentation highlighted a few libraries that'll fix some annoying java aspects like datetime e.d.

Personally, I liked the talk about JavaFX the most. Those graphics just rock! I'm very curious how this gui-scripting-language will 'connect' to existing java objects (or is it for webdevelopment only?). Will definitely check it out in December!

Best regards,
Robin Wagenaar.