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Tuesday, November 19, 2013

Devoxx 2013 - The coming of lambda

It’s November 2013 and it’s conference time again. The European Java and Web Community gathered in Antwerp for the annual DEVOXX conference, which always means days tightly packed with information. My head is still spinning but I’d like to highlight a few things which are noteworthy this year. But first, a picture from the first keynote session, showing live-DJ-ing with software scripting:

No single hype

This year, there was no unique theme standing out. The hypes of the years past, Mobile, Cloud, NoSQL, BigData, are now regarded as standard. There were still presentations about those topics, but they are “normal” now. This of course is a good thing, although great emotions and extraordinary news are missing.

Java 8 expected with Lambdas and support for parallel execution

There were a lot of talks on Java 8 and on the new features available with Lambdas and functional / declarative programming.  They especially seem to enhance code readability which is important because “reading code is more important than writing code” (Brian Goetz). The most prominent example is the replacement of the infamous anonymous inner classes through lamdbas. This can be seen in the following code sample:

public class MyListener {
  public static void main(String[] args) {
    JButton myAnonymousButton = new JButton("A Button");
    //actionlistener using anonymous class
    myAnonymousButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent ae) {
        System.out.println("anon click!");
    //actionlistener using lambda expression   
    myAnonymousButton.addActionListener(e -> { System.out.println("a lambda click!");

    JFrame frame = new JFrame("Functional Sample");
    frame.add(myAnonymousButton, BorderLayout.CENTER);

Internally, the lambdas are implemented using invokedynamic which was introduced in Java 7. By doing so, the JVM can choose that implementation of the lambda which it sees fit. This is an advantage, since at programming time you don’t necessarily know the concrete circumstances of the runtime environment. On the other hand, the programmer loses control, because he only tells the JVM what to do but not how.
There is also a new stream library coming, which especially intends to simplify parallel programming. I’m not sure how much of a performance gain this can achieve, because it half of the code can be parallelized, the program can only run twice as fast.

Microsoft is Sponsor now           

The Devoxx organizers can be happy, because the “big four” are sponsors now: Google, Oracle, RedHat and Microsoft. Google dominated the talks, while, strangely enough, Microsoft did not show up in any of the presentations (although they had a booth). This is really a chance missed, especially since Windows 8 opened up to the Web and allowed for Windows Applications being written in JavaScript and HTML5.

More crowded, but…

Devoxx 2013 was even more crowded than the conferences of the last years. It was harder to get a seat for the important presentations and it was a pain to get something to eat. This all is ok, if the costs are low (which is true) and if the quality of the presentation content is high (which is not so true anymore). Actually, the quality of the slides was a catastrophy! I cannot remember another conference in the last years where “death by bullet point” was so imminent. Many presenters even read all their slides aloud and some did seem to be on the edge of sleeping (or at least trying to get their listeners to sleep). What’s more, good talks on methodology and architecture were missing, while many presenters focused on detailed features of various (sometimes not so important) frameworks. I also missed great keynote speakers. To wrap it up: quality at Devoxx seems to be on the decline. Maybe it’s because there are a lot of Devoxxes out there now (London, Paris, Kids …). Do they lose focus?


Nevertheless, there were some very interesting and entertaining presentations: The session on Google Glass was absolutely packed and really lived up to the expectations. Another good one was Arun Gupta talking about web sockets. Also, Brian Goetz on details of the JVM and Ludovic Champenois on Google App Engine excelled. Next time, get us more of those, please.

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