The WebFlux is not so black as it is painted

Have you ever came across performance problems due to threads being blocked on I/O operations ? Or have you been thinking about reactive approach in such situation but its first impression made you scary ? If the answer to at least one question is yes - then this workshop will be very useful to you. We will gently enter the world of Reactor and then apply it for non-blocking Web applications using Spring WebFlux. After the whole day you will feel that you have tamed the reactive beast.

Code refactoring with IntelliJ - tips & tricks

Being a software developer you can be sure of one thing - that sooner or later (or rather sooner) you will face refactoring of the code - half the trouble if at least written by you and not someone else :) This process always requires some effort and is error-prone. It turns out, however, that you can help yourself with the functions contained in the IDE to minimize both of the above factors and get through the whole operation unscathed. During the presentation, I will show on several examples how to change the code for the better, dropping the dirty work on IntelliJ. You are invited !

Reactor has died, long live Reactor !

With the introduction of virtual threads in Java 21, it seems that reactive programming became irrelevant. After all, from now on we don't have to sacrifice the readability of our code for its scalability. Does this mean that frameworks like Reactor are definitely gone? Well, no - there are still places where their use can bring direct benefits. What's more - thanks to virtual threads, you can use these libraries in a way that until recently would have been considered a serious error, but now it certainly has its justification. I invite you to a fascinating journey into the land of reactivity in the new version!

Automated testing - a curse or a blessing for the developer ?

Typically, as developers we treat automated tests like an unwanted child or an unpleasant chore. We write them because Sonar requires minimal coverage, or because colleagues in the team will point out their absence in code review - but if these factors were not present, we would most likely give up on them altogether :) Meanwhile, it turns out that test code can become a starting point for improving the quality of legacy code - because we can afford to do more in tests than in production code. In my presentation, I want to show how to use this approach and prove that tests are not as black as they are painted :)

IntelliJ debugger - tips & tricks

Almost every Java developer uses IntelliJ debugger in everyday work – but are we taking advantage of the entire potential of its features? Of course it is impossible to show all of them within the one hour. However we can focus on the most important ones that will make our life easier - among others: - adding non-obtrusive logging - searching for the lost exceptions - altering the execution path (even with going back in time) After the presentation (in form of live coding / debugging) everyone should feel being sufficiently armoured to fight with the dragons / bugs within the code.

The talk has already been delivered at several conferences (including Devoxx Poland) and garnered quite a few complimentary comments, because it shows many useful (and not obvious) techniques that many developers are not aware of - until they see them. A recording from JDD conference is available here: https://youtu.be/An6wyF2vCZ0

Enums on steroids - let's look at sealed classes !

Probably everyone has already become familiar with the mechanism of sealed classes introduced in Java 17. However, in addition to strict control of the class hierarchy, it also allows for the creation of non-obvious (yet facilitating) mechanisms. One of them will be enums on steroids - and that's what I want to talk about. But we won't just stop there - we'll follow the trail of everything that happened up to Java 21. It will definitely be an interesting journey - feel free to join !

The presentation allows to show in an accessible way, using the example of a loan engine (https://github.com/chrosciu/loan-engine), what has been recently changed in Java - up to version 21. Through its delivery, I have been awarded as the best speaker on Java track at 4Developers conference in Poznań. Additionally it would be delivered during Devoxx UK: https://www.devoxx.co.uk/talk/?id=12077. Recording from Geecon 2023 is available here: https://youtu.be/7DjyD_jv5Mc

From developer to trainer - or how I returned to my roots

A few years ago, as a programmer, I realized that I was missing what I always liked most in life - sharing knowledge with others. So I decided to take a leap into the deep end and decided to combine both - becoming an IT trainer. In this lecture, I would like to share with you the path I have taken, the mistakes I have made (and from which I have learned lessons) - but also those nice moments in the life of a trainer that give satisfaction and motivation for further development. If you are wondering whether this career path is for you, but you have doubts - I hope that my lecture will help you dispel them. I cordially invite you!

This is my first lecture in which I do not focus on technical things (as it was before), but I decide to share softer skills. The idea for the lecture itself came from conference discussions - my interlocutors were curious about what it is like to be a trainer and how I got there. That's why I thought it was worth sharing with the public. A large part of the lecture is devoted to descriptions of mistakes I have already made as a trainer - I would like other potential trainers not to have to make them again.