JDD Kraków 2017: Day Two

12 Nov

Episode 85

After summarizing the first day of the JDD conference in the last episode, let’s traditionally move on to day two. I was able to attend almost seven talks, most of them very interesting (technically after-party ended after midnight, so it count as part of both days…)


Neil C. Smith: Write NOW, run anywhere

Since it was the only talk on that hour, I’m assuming it was a keynote. More of a show than the talk actually. Neil, an artist coder, introduced a new definition of Live-coding, where various forms of audiovisual performance are created on the fly through writing code. Each line of code might be another sound in a loop or another live camera feed transformation. Neil presented Praxis LIVE – a dedicated IDE for Live-coding, offering various tools to enhance the experience. I always thought that coding lies in a near proximity of art (with fire extinguishing elements), but this takes it to another level.

Sławek Sobótka: DDD Q&A, what troubles conscious programmers

At the beginning, there was chaos, let there be greenfield. DDD was just an excuse to talk about many important things in software development, on various levels of abstraction, both technical and business. We can describe our system by pieces of it that “are”, “behave” and “become”. There are objects and aggregates. We should not operate on objects directly, but let the work done be a side effect of object representation transfer, just like in an office. Business analysis and understanding of client needs are important, as well as right boundaries between contexts. REST API might not be good everywhere. Running the company has different metaphors, far older than the concept of business, game, journey, farming, and sadly the most common in here: war. Very insightful talk.


Michał Wroński: Modern DevOps with Kubernetes

The IT world is getting crazy about containers and their orchestration. Michał introduced Kubernetes on live example. There was pod configuration details, difference between liveliness probe and readiness probe, replica sets, updates, auto-scaling system metrics and custom metrics, monitoring, publishing and other topics including quick comparison of cloud providers as the cloud is where container orchestration truly shines. At the end of journey to DevOPs, there is a promise of idempotence, simplification, standardization and easier local development. The way to DevOps is a long process though. Use Kubernetes, if you have more than 10 microservices, high resource utilization is critical for you and you want to be independent from cloud providers that offer their own specific orchestration services.

Jarosław Pałka: Beyond Event Horizon – what should we expect in Java 10

Java 9 is finally out, time to look what’s coming in the next major release. Jarek started with project Valhalla – value types. Code like a class, works as an int. The idea is to take advantages from both classes and primitives. Then we had primitive collections that will require quite a lot changes in JVM. Project Panama aims at simplifying work with native code – something untouched in Java for a very long time. Project Amber – an umbrella for various small enhancements like pattern matching in switch statements, local variable type inference, generics support in enum and various leftovers from Lambda. I’m often choosing talks on conferences based on speaker, not the topic, and I wasn’t disappointed this time as well.


Robert Szarejko: What back-end developer should know about security

Second security talk I’ve attended, but more cryptography inclined. There was a bit of history and future, from Vermont cipher through Diffie – Hellman math to quantum key distribution and Shor’s algorithm. Take a look at Open Web Application Security top 10 project, block password auto completion by the browser – with appropriate hidden fields on the form, if need be. Use HTTP Strict Security Policy, salt passwords, verify on backend including actual content types of request bodies. Be careful about HTTP Public Key Pinning, XML external entities, and as usual XSS and CSRF attacks. The talk seemed a bit chaotic at the beginning, but it was entertaining and full of good info, only partially overlapping from the one from previous day.

Michał Borkowski: Why every developer should keep reading fiction.

How many books have you read last year? I noticed that in my case these numbers suffers compared to few years ago, and not only because of lack of time. Ubiquity of smartphones and online services changed thy way we expect and process information. The noise of about incomplete, chaotic, incoherent and outdated information is bad for us. Reading book on the other hands is a form of mental hygiene. Exercises our ability to focus for prolonged periods, increase memory responsible for handling large contexts in its entirety and broadens our vocabulary.  Reading technical books gives a well-structured and comprehensive knowledge on the subject than scraps of articles over the internet. Excellent talk, one of those that makes you stop for a moment and think.


It was a great experience. Perhaps JDD does not have that many internationally recognized speakers when comparing to GeeCon conference held the same city, but overall quality was at the same level or even better. Cool atmosphere and afterparty are also notable perks of the event. I’ve met in person lot of people I had contact with on Twitter and other social media as well as colleagues from different site of my company and completely new fellows. If only weather was a bit better… what can you do though?

I’d like to hereby say thank you to organizers for inviting me. I’m looking forward to the next edition, keep up the good job!



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Posted by on November 12, 2017 in Events, News, Technology


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