Scala Days 2018

In 2018 I visited Scala Days in Berlin with this schedule. Other than in previous years I missed the opening keynote, which is traditionally on the evening before the main conference starts, because this is not so well compatible with my choice of traveling with a night train, especially because I did not want to miss more than two days of my current project.

I might provide Links to Videos of the talks, if they become available, including the interesting keynote that I have missed.

So I did visit the following talks on the first full day:

And on the second full day:


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Scala Days 2016

I have visited Scala Days in Berlin 2016-06-15 to 2016-06-17. A little remark on the format might be of interest. The conference is scheduled for 3 days. On the first day, there is only one speech, the first keynote, some time in the late afternoon. During Scala Days 2015 the rest of the day was put into use by organizing a Scala training session, where volunteers could teach Scala to other volunteers who wanted to learn it. But I think two or three sessions on the first day would be better and would still allow starting in the late afternoon with the first keynote. The venue and of course Berlin were great and I enjoyed the whole event.

The talks that I visited were:

Wednesday 2016-06-15

  • First keynote: Scala’s Road Ahead by Martin Odersky about the future of Scala. Very interesting ideas for future versions that are currently explored in dotty.

Thursday 2016-06-16

Friday 2016-06-17


The whole event was great, I got a lot of inspiration and met great people. Looking forward to the next event.

I might write more on some topics, where I consider it interesting, but for the moment this summary should be sufficient.


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Scala Days 2015

I have visited Scala Days 2015 in Amsterdam.
As usual, I took the night train to get there and back.

Creative Scala

Prior to the conference we did a training session for Scala beginners together with underscore. Some volunteers, including myself, joined the effort and so we were actually more teachers than students. It was fun.

Talks I listend to:

Monday 2015-06-08

* Monday-Keynote: Scala – where it came from, where it’s going / Martin Odersky

Tuesday 2015-06-09

* Tuesday-Keynote: Life Beyond the Illusion of Present / Jonas Bonér
* GraphX: Graph analytics for insights about developer communities / Paco Nathan @pacoid
* Meerkat parsers: a general parser combinator library for real programming languages / Ali Afroozeh @afruze & Anastasia Izmaylova @IAnastassija
* Fixing Reactive Code at 100 Miles per Hour: Five Techniques to Improve How You Debug Scala and Akka / Tal Weiss @weisstal
* Options in Futures, how to unsuck them / Erik Bakker @eamelink
* State of the Meta, Summer 2015 / Eugene Burmako @xeno_by
* Function-Passing Style, A New Model for Asynchronous and Distributed Programming / Philipp Haller @philippkhaller & Heather Miller @heathercmiller
* Essential Scala: Six Core Principles for Learning Scala / Noel Welsh @noelwelsh
* Project Gålbma: Actors vs. Types / Roland Kuhn @rolandkuhn

Wednesday 2015-06-10

* Wednesday-keynote: The Future of AI in Scala, and on the JVM / Adam Gibson
* Why Spark Is the Next Top (Compute) Model / Dean Wampler @deanwampler
* The Reactive Streams Implementation Landscape / Mathias Doenitz @sirthias
* Reactive Slick for Database Programming / Stefan Zeiger @StefanZeiger
* So how do I do a 2-phase-commit with Akka then? / Lutz Huehnken @lutzhuehnken
* Functional Data Validation (or How to Think Functionally) / Dave Gurnell @davegurnell
* Don’t Block Yourself / Flavio Brasil
* Closing Panel and Thank You

More details will come…

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Scala Days in Berlin 2014


Around mid of June 2014 I have been visiting the Scala Days in Berlin. Like usual these events contain a lot of speeches, which were distributed in four tracks, apart from the key notes. The event location was a cinama, like the Devoxx in Antwerp, but this time one that has been transformed to something else many years ago, but good projectors were available. Major topics where issues about compiler construction which is a hard task, but looked at with the right functional perspective it can be derived from the simple task of writing an interpreter. This helps understanding language constructs in Scala, but the idea was applied to many other areas as well, for example for compiling and optimizing SQL queries and for analyzing source code.

Another major topic was „streams“, which can be useful for web services. Other than traditional web services which usually receive the whole request before starting to process it, concepts where discussed for dealing with large requests whose size is painful or impossible to keep at once in memory or who are even unlimited in size. These can also be applied to websockets. This demands processing data as soon as useful parts have arrived.

Another minor, but very interesting topic was development of Android apps with Scala. The commonly known approach is off course Scaloid, but an alternative, Macroid, was presented. It looked quite promising, because it allows to write nice Android apps with less code. A major worry is that scala apps consume too much memory due to their additional libraries. Because Scala uses its own libraries on top of the usual preinstalled Java libraries which are about 5 MB in size, this can easily anihilate the attractiveness of Scala for modern smart phone development, unless we assume rooted devices which have the Scala libs preinstalled. But that would seriously limit the scope of the app. This is not as bad as it sounds, because the build process contains one step in which unnecessary classes are removed, so that we only install what is really needed. When going as crazy as running Akka on the cell phone it becomes quite a challenge to configure this step because Akka uses a lot of reflection and so all these reflective entry points need to be configured, leaving a wide door open for bugs that occur at runtime when some class is not found.

API design was another interesting talk. Many ideas were quite similar to what I have heard in a API design traing for the Perl programming language by Damian Conway a couple of years ago, but off course there are many interesting Scala specific aspects to the topic. It is surprisingly hard to obtain binary compatibility of classes and this even forces to ugly compromises. So always recompiling everything looks tempting, but is not always reasonable. So ugly compromises remain part of our world, even when we are working with Scala.

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