DDevelopment & Design

4Developers 2010 Review

I’ve been to 4Developers in 2009 in Cracow, together with Tomasz Przybysz and we had very nice impressions, no wonder then I wanted to signed up for 2010 edition in Poznań as well. Tomasz was sick, but Jakub Kurlenda decided to come with me. This time…I’ve been to 4Developers in 2009 in Cracow, together with Tomasz Przybysz and we had very nice impressions, no wonder then I wanted to signed up for 2010 edition in Poznań as well. Tomasz was sick, but Jakub Kurlenda decided to come with me. This time…

I’ve been to 4Developers in 2009 in Cracow, together with Tomasz Przybysz and we had very nice impressions, no wonder then I wanted to signed up for 2010 edition in Poznań as well. Tomasz was sick, but Jakub Kurlenda decided to come with me. This time our company was sponsoring the conference so I had a stand-up banner to carry.

Getting up at 4am is annoying, and you need to get up so early to get to Poznań by car. Thanks god it was  Friday, I could be dangerous if woken up at this hour on Saturday.

After arrival we were invited by high-heels hostesses. Now I’ll be a bit stereotypical programmer for a while: what on earth are so lovely hostesses doing on an IT conference? Yeah, sure they look nice, but hey, I thought I’m paying my money for the knowledge. If I wanted to go for good looking girls, I’d visit a local Salsa club. The best high-heels can do is distract me. And I’d rather you spend my bucks on better food, more speakers or just lower the price instead of this.

Unless, of course, these were local IT students helping for free. I strongly doubt if Poznań has so many female IT students all together in all its higher education facilities, but if that is the case, I’m starting to regret I’ve not moved to Poznań.

While I am at the organizational part, lets say that the rest was quite flawless, with tasty sandwiches, drinks, cookies and console games in between lectures. Two exceptions were: a bad lunch, served at Orbis Polonez hotel (and a total rip-off at 50zł) and no place to sit down while outside of conference rooms.

Not that we had any time, mind you. All the presentations had a tendency to take more than scheduled, and while it’s quite fine with me (it actually means there are people who’d rather listen than go for a cookie and coffee), the host didn’t seem to like it much. I think there should be more buffer time for breaks or maybe even an open space in between, to make everyone happy.

Fighting for live

Let’s get back to the lectures. The conference had four tracks, and I’ve started with ‘Fighting for live – derivatives and successors of Java are taking over the world’ by Michael Hunger. That was a big disappointment. Michael was way too theoretical. I’m afraid nothing from his speech would be useful to anyone in the room. And he didn’t give us much more than what we can actually find on wikipedia: just a brief list of some from 400+ languages running on JVM. The only interesting parts were actually played from youtube. I’ve not been waking up at 4am to watch youtube in Poznań. I can do it back home, you know.  As I said, a total disappointment.

Microsoft Cloud: Windows Azure

Angry and sad at the same time, I’ve decided to switch rooms to see Maarten Balliauw talking about Windows Azure. I’ve been thinking about using Google App Engine for my next project, so I wanted to know what Microsoft has to offer in terms of cloud computing. And boy, they do have stuff in there.

Maarten gave us a quick overview of a few projects surrounding the M$ cloud, and after that showed us how to move a simple ASP.NET application to Azure. Jakub Kurlenda, who I believe never had a chance to work with .NET, was amazed. It can't be that simple – he said – There's got to be a lot of problems with complex solutions. Well my friend, remember that M$ has inherited all the good stuff from Borland togethere with Anders Hejlsberg. Sure it sometimes doesn’t work perfectly, but still their tools are quite sexy. And way easier than anything you can find in Java world.

The Microsoft Azure does look very interesting. You get an MS SQL, Storage Service for unstructured data, front end web servers, back end servers and a AppFabric Service Bus to connect different services in a via-VPN-like manner. You even get an information marketplace Codename “Dallas”, to sell and buy services and data. Now this sound like an App Store of cloud computing, doesn’t it?

I think the war between cloud computing providers is going to be quite a show soon. And no matter whoever wins, I think that Microsoft won’t lose.

Not so Funky It Management

For the third lecture I’ve visited the IT Management track, where Peter Horsten, a guy who moved from Netherlands to Poland to create his company (Goyello) in Gdańsk, gave a speech about Funky It Management, but after half an hour I’ve returned to Java track uninspired. Peter is a great speaker, but for the first thirty minutes I heard nothing I could actually use or didn’t know already, so I wasn’t going to risk the rest of the time.

TopLink Grid and Oracle Coherence

That made me see only half of presentation from Waldemar Kot about TopLink Grid and Oracle Coherence, and I really regret that. Waldi, as he is sometimes called by friends (and notoriously by Jacek Laskowski) works for BEA… errr… Oracle, and while I do not know whether he is only consulting or also building systems for his clients, he is sharp as a Gillette, precise as a laser and full of knowledge. I really enjoyed his talk, there was a nice mix of theory and practice, and finally, some stuff I could actually use at work. Thanks Waldi.

Flex 4 and iPhone news

After a horrible lunch, Piotr Walczyszyn gave us a tutorial in using Flex 4. Years ago, I had a chance to use AMF to communicate between a heavy Flash frontend and a PHP backend, and it worked quite well. I have to note that especially debugging was nice, something I wouldn’t expect from a binary and proprietary format. For the last two years, I’ve been hearing about how easy it is to have a Java backend and Flex rich frontend. A lot of people I’ve met at the last year’s GeeCON conference actually worked that way. I was very interested in the topic and after the show I can tell you this, Flex is a way to go if you want to have a rich (heavy?) Intranet client. I think though, that its use for public/Internet services should be considered carefully. Too much bells and whistles and you are going down on frontend complexity and throughput. But you already know that, don’t you?

If using Java, I’d go for Flex 4 if Wicket is not rich enough for the solution. If Wicket is fine, I’d stay away from anything more complex (and difficult to test). I don’t have a lot of love for GWT, after what I’ve seen at work. But that could be a GXT fault, not a Google failure.

One of the most interesting news Piotr spread, was that Flex is being implemented on Android and… wait for it… iPhone! How’s that possible, you ask? We all know Apple doesn’t want to loose its AppStore market to on-line flash applications. Well, they are building a native Flex to Objective-C compiler, that’s how. If they manage to implement a runtime on Symbian and Windows Mobile, it may be the only truly portable technology. Unless you call HTML 5 a programming language, of course.

Java SE 7

After that Marcin Katas was talking about Java SE 7, which is scheduled for the end of this year. There was a lot about new Garbage Collector, that I don’t really care about, a few thing about OSGi-like solutions to dependency hell,  support for dynamic languages, new concurrency classes, closures and  Project Coin (small changes/additions to the language).

The only thing I can say is: why so late? And why so little?

Especially for Project Coin.  This is actually quite sad. Java as a language is being left behind its competitors. Really, Automatic Resource Management is a concept implemented YEARS ago with using in C#. Come on people, I’d at least expect stuff like .NET LINQ in new version of JDK, not even mentioning some long needed fixes for stuff like collections and generics. It’s been four long years since Java SE 6, there should be a Java SE 8 already.

I really think they should release a new version in a fixed interval of time, like Ubuntu is doing, like it was before Java SE 6. And forget about the hardcore backward compatibility, like with fu…-up generics. Banks that are still using J2SE 1.4 are not updating anyway.

Sobótka on Craftsmanship

And finally, I’ve been waiting for this one, Sławomir Sobótka, owner of Bottega, guy whose blog I’m actively reading, shared his thoughts about software craftsmanship.

That was by far the best presentation at the conference. Absolutely brilliant. I would not be able to put more meaningful information in such a short time and accessible way even had I tried for months. And to be honest, that was also the most important subject, useful to everyone, touching the work of every software developer in the room (and in the other .NET room as well). Kudos to you Sławek.

Too bad, there wasn’t anything new to me then. But maybe I should be actually glad, maybe it means I’m keeping up with the front line. Maybe, or maybe we are just reading the same books, groups and feeds (or I’m reading his blog actually). Anyway, I’m very happy about this lecture. What a beautiful world would it be if everyone was as passionate for craftsmanship and quality as  Sławek is.

I didn’t make it for OSGi speech from Jacek Laskowski. Sorry Jacek, but waking up at 4am doesn’t leave you a lot of strength for the last lecture. I’ve seen Jacek in action a few times, and it’s always a pleasure as he is a great showman (in a positive sense). I hope I’ll see you again at Warsaw’s JUG meetings, but now I’d rather get back to bed before midnight than get sick after the conference like all my friends did. Yeah, I’ve heard that Jakub Kurlenda got down just like Tomasz Przybysz a week ago, after the Winter Agile Tunning.

The price of knowledge has always been high, I guess.

Alltogether it was a very interesting conference and definitely worth the money.

Reviews (in Polish) from others can be seen here and here and here and here.

Solution Architect @ TouK

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DDevelopment & Design

New HTTP Logger Grails plugin

I've wrote a new Grails plugin - httplogger. It logs:

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It is mostly useful for logging your REST traffic. Full HTTP web pages can be huge to log and generally waste your space. I suggest to map all of your REST controllers with the same path in UrlMappings, e.g. /rest/ and configure this plugin with this path.

Here is some simple output just to give you a taste of it.

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Official plugin information can be found on Grails plugins website here: http://grails.org/plugins/httplogger or you can browse code on github: TouK/grails-httplogger.

DDevelopment & Design

33rd Degree day 2 review

Second day of 33rd had no keynotes, and thus was even more intense. A good conference is a conference, where every hour you have a hard dilemma, because there are just too many interesting presentations to see. 33rd was definitely such a conference, and the seconds day really shined.

There were two workshops going on through the day, one about JEE6 and another about parallel programming in Java. I was considering both, but decided to go for presentations instead. Being on the Spring side of the force, I know just as much JEE as I need, and with fantastic GPars (which has Fork/Join, actors, STM , and much more), I won't need to go back to Java concurrency for a while.

GEB - Very Groovy browser automation

Luke Daley works for Gradleware, and apart from being cheerful Australian, he's a commiter to Grails, Spock and a guy behind Geb, a  browser automation lib using WebDriver, similar to Selenium a bit (though without IDE and other features).

I have to admit, there was a time where I really hated Selenium. It just felt so wrong to be writing tests that way, slow, unproductive and against the beauty of TDD. For years I've been treating frontend as a completely different animal. Uncle Bob once said at a Ruby conference: "I'll tell you what my solution to frontend tests is: I just don't". But then, you can only go so far with complex GUIs without tests, and once I've started working with Wicket and its test framework, my perspective changed. If Wicked has one thing done right, it's the frontend testing framework. Sure tests are slow, on par with integration tests, but it is way better than anything where the browser has to start up front, and I could finally do TDD with it.

Working with Grails lately, I was more than eager to learn a proper way to do these kind of tests with Groovy.

GEB looks great. You build your own API for every page you have, using CSS selectors, very similar to jQuery, and then write your tests using your own DSL. Sounds a bit complicated, but assuming you are not doing simple HTML pages, this is probably the way to go fast. I'd have to verify that on a project though, since with frontend, too many things look good on paper and than fall out in code.

The presentation was great, Luke managed to answer all the questions and get people interested. On a side note, WebDriver may become a W3C standard soon, which would really easy browser manipulation for us. Apart from thing I expected Geb to have, there are some nice surprises like working with remote browsers (e.g. IE on remote machine), dumping HTML at the end of the test and even making screenshots (assuming you are not working with headless browser).

Micro services - Java, the Unix Way

James Lewis works for ThoughtWorks and gave a presentation, for which alone it was worth to go to Krakow. No, seriously, that was a gem I really didn't see coming. Let me explain what it was about and then why it was such a mind-opener.
ThoughtWorks had a client, a big investment bank, lots of cash, lots of requirements. They spent five weeks getting the analysis done on the highest possible level, without getting into details yet (JEDI: just enough design initially). The numbers were clear: it was enormous, it will take them forever to finish, and what's worse, requirements were contradictory. The system had to have all three guarantees of the CAP theorem, a thing which is PROVED to be impossible.
So how do you deal with such a request? Being ThoughtWorks you probably never say "we can't", and having an investment bank for a client, you already smell the mountains of freshly printed money. This isn't something you don't want to try, it's just scary and challenging as much as it gets.
And then, looking at the requirements and drawing initial architecture, they've reflected, that there is a way to see the light in this darkness, and not to end up with one, monstrous application, which would be hard to finish and impossible to maintain. They have analyzed flows of data, and came up with an idea.
What if we create several applications, each so small, that you can literally "fit it in your head", each communicating with a simple web protocol (Atom), each doing one thing and one thing only, each with it's own simple embedded web server, each working on it's own port, and finding out other services through some location mechanism. What if we don't treat the web as an external environment for our application, but instead build the system as if it was inside the web, with the advantages of all the web solutions, like proxies, caches, just adding a small queue before each service, to be able to turn it off and on, without loosing anything. And we could even use a different technology, with different pair of CAP guarantees, for each of those services/applications.
Now let me tell you why it's so important for me.
If you read this blog, you may have noticed the subtitle "fighting chaos in the Dark Age of Technology". It's there, because for my whole IT life I've been pursuing one goal: to be able to build things, that would be easy to maintain. Programming is a pure pleasure, and as long as you stay near the "hello world" kind of complexity, you have nothing but fun. If we ever feel burned out, demotivated or puzzled, it's when our systems grow so much, that we can no longer understand what's going on. We lose control. And from that point, it's usually just a way downward, towards complete chaos and pain.
All the architecture, all the ideas, practices and patterns, are there for just this reason - to move the border of complexity further, to make the size of "possible to fit in your head" larger. To postpone going into chaos. To bring order and understanding into our systems.
And that really works. With TDD, DDD, CQRS I can build things which are larger in terms of features, and simpler in terms of complexity. After discovering and understanding the methods (XP, Scrum/Kanbad) my next mental shift came with Domain Driven Design. I've learned the building block, the ideas and the main concept of Bounded Contexts. And that you can and should use a different architecture/tools for each of them, simplifying the code with the usage patterns of that specific context in your ming.
That has changed a lot in my life. No longer I have to choose one database, one language and one architecture for the whole application. I can divide and conquer, choose what I want to sacrifice and what advantages I want here, in this specific place of my app, not worrying about other places where it won't fit.
But there is one problem in here: the limit of technologies I'm using, to keep the system simple, and not require omnipotence to be able to maintain, to fix bugs or implement Change Requests.
And here is the accidental solution, ThoughtWorks' micro services bring: if you system is build of the web, of small services that do one thing only, and communicate through simple protocol (like Atom), there is little code to understand, and in case of bugs or Change Requests, you can just tear down one of the services. and build it anew.
James called that "Small enough to throw them away. Rewrite over maintain". Now, isn't that a brilliant idea? Say you have a system like that, build over seven years ago, and you've got a big bag of new requests from your client. Instead of re-learning old technologies, or paying extra effort to try to bring them up-to-date (which is often simply impossible), you decide which services you are going to rewrite using the best tools of your times, and you do it, never having to dig into the original code, except for specification tests.
Too good to be true? Well, there are caveats. First, you need DevOps in your teams, to get the benefits of the web inside your system, and to build in the we as opposite to against it. Second, integration can be tricky. Third, there is not enough of experience with this architecture, to make it safe. Unless... unless you realize, that UNIX was build this way, with small tools and pipes.
That, perhaps. is the best recommendation possible.

Concurrency without Pain in Pure Java

Throughout the whole conference, Grzegorz Duda had a publicly accessible wall, with sticky notes and two sides: what's bad and what's good. One of the note on the "bad" side was saying: "Sławek Sobótka and Paweł Lipiński at the same time? WTF?". 
I had the same thought. I wanted to see both. I was luckier though, since I'm pretty sure I'll yet be able too see their presentations this year, as 33rd is the first conference in a long run of conferences planned for 2012. Not being able to decide which one to see, I've decided to go for Venkat Subramaniam and his talk about concurrency. Unless we are lucky at 4Developers, we probably won't see Venkat again this year.
Unfortunately for me, the talk ("show" seems like a more proper word), was very basic, and while very entertaining, not deep enough for me. Venkat used Closure STM to show how bad concurrency is in pure Java, and how easy it is with STM. What can I say, it's been repeated so often, it's kind of obvious by now.
Venkat didn't have enough time to show the Actor model in Java. That's sad, as the further his talk, the more interesting it was. Perhaps there should be a few 90min sessions next year?

Smarter Testing with Spock

After the lunch, I had a chance to go for Sławek Sobótka again, but this time I've decided to listen to one of the commiters of Spock, the best thing in testing world since Mockito. 
Not really convinced? Gradle is using Spock (not surprisingly), Spring is starting to use Spock. I've had some experience with Spock, and it was fabulous. We even had a Spock workshop at TouK, lately. I wanted to see what Luke Daley can teach me in an hour. 
That was a time well spent. Apart from things I knew already, Luke explained how to share state between tests (@Shared), how to verify exceptions (thrown()), keep old values of variables (old()), how to parametrize description with @Unroll and #parameterName, how to set up data from db or whatever with <<, and a bit more advanced trick with mocking mechanism. Stubbing with closures was especially interesting.

What's new in Groovy 2.0?

Guillaume Laforge is the project lead of Groovy and his presentation was the opposite to what we could see earlier about next versions of Java. Most visible changes were already done in 1.8, with all the AST transformations, and Guillaume spent some time re-introducing them, but then he moved to 2.0, and here apart from multicatch in "throw", the major thing is static compilation and type checking.
We are in the days, were the performance difference between Java and Groovy falls to a mere 20%.  That's really little compared to where it all started from (orders of magnitude). That's cool. Also, after reading some posts and successful stories about Groovy++ use, I'd really like to try static compilation with this language
Someone from the audience asked a good question. Why not use Groovy++ as the base for static compilation instead. It turned out that Groovy++ author was also there. The main reason Guillaume gave, were small differences in how they want to handle internal things. If static compilation works fine with 2.0, Groovy++ may soon die, I guess.

Scala for the Intrigued


For the last talk this day, I've chosen a bit of Scala, by Venkat Subramaniam. That was unfortunately a completely basic introduction, and after spending 15 minutes listening about differences between var and val, I've left to get prepared to the BOF session, which I had with Maciek Próchniak.

BOF: Beautiful failures


I'm not in the position to review my own talk, and conclude whether it's failure was beautiful or not, but there is one things I've learned from it.
Never, under none circumstances, never drink five coffees the day you give a talk. To keep my mind active without being overwhelmed by all the interesting knowledge, I drank those five coffees, and to my surprise, when the talk started, the adrenaline shot brought me over the level, where you loose your breath, your pulse, and you start to loose control over your own voice. Not a really nice experience. I've had the effects of caffeine intoxication for the next two days. Lesson learned, I'm staying away from black beans for some time.
If you want the slides, you can find them here.
And that was the end of the day. We went to the party, to the afterparty, we got drunk, we got the soft-reset of our caches, and there came another day of the conference.

You can find my review from the last day in here.