December meetup: Spring with Kotlin and Property delegation

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Lightning Talk: Was it worth it? — 5 months after starting new project with Kotlin & Spring (Talk in Polish)
by Piotr Janczyk

Kotlin recently gains popularity for backend development. How well does it work with Spring, WebFlux, MongoDB and others? In the talk I will mention its advantages over Java but also tell you about problems with integrating Kotlin with Java libraries.

Enthusiast of various technologies — from assembly to functional programming. Recently fascinated with Kotlin which he used for both backend and Android projects.

Talk #1: Property delegation in Kotlin. Best practices for Android.
by Samuel Urbanowicz

Java and Scala's open-source ecosystem faces several challenges. Writing The presentation will explain the concept of property delegation in Kotlin from scratch by presenting easy to follow code examples. In the beginning, it will point out the advantages of property delegation in Kotlin which allow modularizing the code efficiently and show step by step how to implement a custom property delegate. Next, it will present basic property delegates available in the standard library, show their applications and explain implementation. Finally, it will show useful applications of property delegation on Android and explain the cost of using delegation on JVM by analyzing its compiled representation.

The presentation will consist of the following parts:
1. Property vs field
2. Delegated property concept
3. Standard library property delegates
4. Best practices for Android
5. The hidden costs

Samuel is a Software Engineer @Netguru. He's in love with Kotlin since its beta version. He's an author of the Kotlin Standard Library Cookbook handbook. Off-the-clock he climbs a lot and develops chatbots.

Talk #2: To Be Continued - multithreading with Project Loom and Kotlin's Coroutines
by Artur Skowroński

Both Kotlin and Java are languages that are heavily used in Distributed Systems, handling multiple asynchronous operations simultanouesely. Blocking is not an option in such an environment, but let’s be honest, we crave for easier synchronous world. That’s why JVM as a platform have inherent focus on providing easier option of multithreaded programming. Today, I’d like to compare two of such options - Kotlin Coroutines and Project Loom, that want to provide fibers and continuations to core Java.


Developer with heart cracked between JS and JVM stacks (with more mature relationship and advanced marriage plans with JVM), with fingers chopped from playing with bleeding edge technologies... hard way.

Currently proudly working for VirtusLab, mainly (but not only) on projects for Tesco Technology.

Part of Dynamic Duo which better part is his plush seal ᶘ ᵒᴥᵒᶅ

JetBrains provided free licence to rafle during the meetup.
VirtusLab is the founding sponsor of Kraków Kotlin User Group.