Sharing knowledge is one of our core values and as lot's of research confirms knowledge transfer is best done between peers. We have a great knowledge sharing platform at Xebia through bi-weekly evening sessions, where we do some experimental coding and some presentations. Once in a while we take it to the max and organise a tech rally. One of those happened last Friday and it was a total blast. I'll give you some of the highlights. More detailed posts on the technical details will follow and I'll update the list below as they do:


We started out with a picture and a maven skeleton and starting code for some tricky parts. Graciously prepared by Albert Sikkema.
This image was the only visual aid in the presentation of the case, causing much skepticism and questions about lack of preparation. These early moments of uncertainty were casually ignored during development.

From there we split up in 4 teams and chose common sense and utter anarchy as a methodology.

Javascript flamewars

Prior to the tech rally we had a good old flamewar between javascript zealots and heretics. One of the best moments was when Gerbrand, who isn't a big fan of javascript turned up as the first volunteer to work on the javascript needed for the front end. The end result was cuddly like a baby bear, I'm really curious to hear if Gerbrand has been converted to the dark arts. I couldn't find the JSUnit testcases, but that's a topic for another day.

Spring REST

To render JSON to a client it is tempting to try out a REST framework. To keep things simple we went for Spring REST and the result was as expected. There were a few hick-ups related to setting the content type or facing the 406, but luckily no fairies got killed. The details of this little trick have been described already on the Spring blog, but if you need a working sample you can also have a look at our web project.

Reading email with Spring Integration

Through no influence of yours truly (boy scouts honor) we ended up using Spring Integration to read mails from a gmail account. I avoided joining that team, but I had the pleasure of joining in one particularly interesting discussion on preferred granularity of pipes and filters. The answer I came up with could fill another blog, but the question is more interesting anyway, so I'll just give you that.

When should we use a synchronous channel and when is it better to just call the method directly?

In other words: how big should endpoints become before you split them up? Think on that and let me know if you have figured it out.

Dealing with javax.mail, even through a framework is a daunting exercise. Andrew Snare (who recently joined us) found a really tricky one, Albert Sikkema found a couple more during the preparations. Because of this, intelligent folder management was not one of our achievements during the day. We did however read the mail successfully and store it in our database. Good enough for a first prototype.

Storing the posts in MongoDB

At Xebia we're involved in a number of initiatives around NoSQL, most notably the NoSQL Meetups organized by Wilfred. Obviously we cannot store data in a traditional database for fun anymore. Even though the MongoDB part of the application might be the coolest bit on paper the work there was minimal. MongoDB is just too easy to use.
Being in the MongoDB team was pretty cool nonetheless, because being the main integration point of a 20 developer 4 team commit frenzy is the closest thing to being in a warzone I ever hope to experience.

The coolest thing was that at the end, the application actually worked. Nobody got hurt and we could show an end to end demo of the whole thing at five in the afternoon.

This rally was exactly the kind of experience I was looking for when I joined Xebia, so I was totally thrilled. The only thing left to do is find a customer that allows us to really go crazy like that. Any takers?