DroidCon Poland: Is your app really connected?

2017-12-02 Android, Conferences No comments

Yesterday, I gave a presentation about connectivity in the Android apps during the DroidCon Poland 2017 Conference in Kraków.

Below, you can see slides from this presentation.

There’s also tweet related to this presentation from DroidCon Kraków:

I hope, you enjoyed it. Any kind of feedback is welcome (in the comments below this article or via e-mail).

Don’t forget to check ReactiveNetwork library I mentioned during the presentation.

5 ways to attend expensive IT conferences for (almost) free

2017-11-02 Conferences No comments


In the past months, I’ve attended a few conferences and meetups related to IT. I also plan to attend a few more in the last quarter of the year as a speaker. I’d like to show you a few tips, which can encourage you to attend such events, be more involved in them and spend some time away from your desk ;-). If you are working in a software company, in the most cases you could treat going for a conference as a non-customer facing business trip, so your regular days off will be safe and can be used for your personal plans and holidays :-).
I tried all of the methods described in this article both in Poland and abroad, so I can tell you they’re confirmed in practice.

Use your company’s educational budget

There are companies, which offer so called educational budget, which is defined each year. Such budget can be used for attending the conferences and trainings. In the company where I work now (SAP Hybris), I have such benefit and I could use it to go to the Spring I/O in the Barcelona, Spain last year, J On The Beach in Malaga, Spain and Devoxx in Kraków, Poland this year. Of course, travel, food and accommodation expanses were covered by this budget as well as conference tickets.

ICE Kraków Congress Centre – Devoxx Poland 2017 Venue

Malaga, Spain

Be a speaker

This year I was a speaker during JDD conference in Kraków, Poland. I had confirmed business trip and an accommodation in high quality hotel paid by the conference organizers. I could also attend a dinner with other conference speakers and see all conference talks and hang out with participants without spending a penny. In the December 2017, I’m also going to be a speaker during DroidCon Poland conference, where organizers offered to cover accommodation costs as well. Usually, you can expect that from good quality events, but it may happen that part of the costs will have to be covered by you, so it’s good to be prepared for that.

My JDD 2017 Conference Talk in Kraków, Poland

Be a rejected speaker

I’ve send my submission during Call For Papers for GDG Dev Fest in Lviv, Ukraine. I was rejected, but organizers offered me a free conference ticket. Organizers had over 150 C4P submissions including those of people from Google, Twitter, etc., so I wasn’t lucky this time. Ukraine is quite cheap country comparing to Poland and I wanted to visit Lviv, so I paid for travel and accommodation by myself and joined this event.

GDG Dev Fest Ukraine 2017 Conference in Lviv

View from Pravda Beer Theatre on the Market Square in Lviv, Ukraine

Be a blogger

I create this blog for a few years and I think its quality is becoming better and better every year and more people visit it. Last year, JDD conference organizers offered me a free conference ticket in exchange for promoting their conference on my blog. It was good exchange, because this event is interesting and related to the content of my website. In addition, conference ticket is not so cheap and costs about ~500 PLN or something like that. This situation encouraged me to be more engaged in the Java community and this year I attended the same conference as a speaker.

Be a volunteer

From a long time I wanted to visit London in UK and attend DroidCon London conference as well. It’s one of the most popular Android conferences in the Europe. Conference ticket is very expansive and costs 695 GBP, which is approximately ~3352 PLN. Nevertheless, you can save some money if you buy it very early (like almost one year before the conference). I used most of my personal educational budget in the company and I could, but I didn’t want to spend such amount of money from my own pocket just for a conference ticket. I’ve sent to the organizers a proposal of promotion of their event on my blog in exchange for a free conference ticket. They didn’t really want that, but they asked me to be a volunteer for a 2 days, so I could help them a little and get the free ticket. I decided to go for it. UK is much more expansive place than any city in Poland, so I had to spend some money for accommodation, food and transportation. Nevertheless, I don’t regret it, because it was nice experience and London is worth visiting at least for a few days. Moreover, I haven’t really encountered typical London weather. There was hot and sunny during my stay. Only one day was a bit cloudy with a small rain, but it wasn’t as cold as in Poland on my way back. I also made a few connections and gave my business cards to a few people. Such kind of networking can create new possibilities related to work, local & global communities, speaking on meetups, conferences etc. Of course, when you go to UK, don’t forget to check out the map of every pub in UK.

Business Design Centre London – DroidCon London 2017 Venue

London, UK in late October 2017 (The Shard is visible in the background)

Tower Bridge visible from The Shard, London, UK


As you can see, there are many ways to attend expensive IT conferences and you don’t really have to spend your own money on the tickets every time. You just need to be in a good company, a bit more engaged, give something from yourself to others and it will bring you profits. Attending many conferences won’t make you the best developer in the world, but sitting in front of your desk and doing the same thing for many days won’t do that either. It’s good to find a balance and time for the new experiences, changing your surroundings for some time, seeing new places and meeting new people. When you can mix that with your profession and work, that’s great!

Meet & Code 2017: “Git – tips & tricks” presentation

2017-10-21 Conferences, Git No comments

Recently, during Meet & Code event organized by Media 3.0 and SAP Hybris, I’ve gave a talk for university and high-school students about basics of Git. Presentation was titled Git – tips & tricks and was organized at the Silesian Univeristy of Technology in the AEI Department where I was studying a few years ago. Presentation covered quite essential usage of Git, which could be helpful for people who are planning to learn it from the scratch. Nevertheless, in the talk I included a few tips, which could be applied even by more advanced users in their daily work. You can view slides from this presentation below.

JDD 2017: Get ready for java.util.concurrent.Flow! – slides, code and recap

2017-10-05 Conferences, Java, RxJava 2 comments

Recently on the JDD 2017 conference, I gave a presentation regarding introduction to Reactive Streams standard in Java 9. I also talked about existing implementations of this standard with the strongest focus on RxJava2 and created simple Reactive Streams implementation in pure Java 9 during the presentation. Below, you can find slides from this talk.

Code snippets shown during this presentation are available at
I have done a tiny live coding session during this talk. Luckily, everything went fine, the code was compiled and executed without errors. Everything I’ve done during this presentation and additional exploratory unit tests could be found in this repository so you can check it out if you’re interested.

There were also tweets made by the audience just before the presentation.

I can say that conference room was full. There were even people sitting on the floor due to lack of free chairs what really surprised me. In the Eventory app, more than 85 people joined the lecture, but in reality, there could be about 100 people or more. It was really flattering that such huge and great audience decided to listen to my talk. In fact, that was the biggest audience I have ever had during the public presentation so far. Moreover, people were asking many interesting questions during Q&A session and after the presentation, so it means they were interested in this topic and they wanted to learn more, understand it and apply it in their projects. If you haven’t had the opportunity to see this presentation, but you would like to, JDD organizers will provide video recordings from the sessions. In addition, you can monitor Talks page on this blog, where I publish my past and upcoming sessions. Probably, I’ll present this topic again during one or two meetups because people are interested in it.

Joining JDD 2017 as a speaker was a great experience. It cost me an additional work and effort after hours, but at the end of the day, it was totally worth it and it was much easier to establish contacts and meet new people as a speaker than as an attendee, what is important for me. Moreover, I could learn new things from other people as well because general level of the conference presentations was pretty high.

Thanks for the interesting questions, discussions, other good presentations and support before the talk!

Below you can find two pictures from this talk made by JDD 2017 photographers.

JDD 2017: Get ready for java.util.concurrent.Flow!

2017-10-02 Conferences, Java, Po polsku, RxJava No comments

Get ready for java.util.concurrent.Flow!

On the 3rd of October 2017 I will be giving a talk titled “Get ready for java.util.concurrent.Flow! at JDD 2017 Conference in beautiful Kraków, Poland.
The talk will be in Polish and you can find a short Polish description of it below.

W Javie 9 otrzymamy do dyspozycji nową klasę z pakietu java.util.concurrent o nazwie Flow. Idea stojąca za tym rozwiązaniem wywodzi się z projektu Reactive Streams. W związku z tym, najnowsza wersja Javy będzie posiadała natywne wsparcie dla tworzenia reaktywnych aplikacji zgodnych ze wspomnianym standardem. Już dziś możemy z tego standardu korzystać i warto się z nim zapoznać wcześniej. Co więcej, od jakiegoś czasu mamy do dyspozycji istniejące implementacje Reactive Streams, które są sprawdzone i gotowe do użycia w projektach na platformę JVM. Wszystkie biblioteki implementujące ten standard mogą ze sobą współpracować dzięki wspólnemu API. Programowanie reaktywne pozwala na pisanie wydajnych aplikacji, które optymalnie wykorzystują zasoby sprzętowe. To podejście pozwala również na dodanie czytelnej warstwy abstrakcji dla aplikacji wielowątkowych oraz wygodne zarządzanie strumieniem danych bez utraty czytelności kodu. Warto dodać, że programowanie reaktywne sprawdza się zarówno na serwerach obsługujących dużą liczbę żądań, jak i na urządzeniach mobilnych, gdzie większość operacji musi być wykonywanych asynchronicznie bez blokowania głównego wątku. Podczas prezentacji chciałbym przedstawić na przykładach popularne implementacje standardu Reactive Streams w Javie 8 takie jak RxJava2 i Project Reactor oraz przykładową, prostą implementację tego samego standardu w Javie 9 z wykorzystaniem klasy java.util.concurrent.Flow.

Date and time of the talk: Day 1, Track 4, Oct 3rd 3:00pm – 3:45pm

This will my very first talk on the JDD conference. I’ve attended this conference a few times as a participant in the past and now it’s time to give a talk as a speaker. I warmly invite everyone who is going to join JDD this year to attend my talk. I’ll try to do my best to keep you interested. There will be an overview of reactive programming, reactive libraries and reactive streams interfaces in Java 9. To keep you awake, we’ll do some live coding and demos on stage.


Due to the fact, I will be speaking on the JDD for the first time, and I’m participating in JUGmajster competition representing SJUG team with two of my colleagues Daniel Pokusa and Grzegorz Gajos. Check out their talks too!

You should also view complete conference schedule. In addition, don’t forget to visit main page of the conference at

If you would like to have a discussion, ask a question or just have a beer together, don’t hesitate to reach me! 🙂

See you in Kraków!

How to make open-source projects, which people want to use

2017-04-01 Conferences, DSP2017, Open source No comments

Today at Kariera IT conference in Katowice, Poland, I presented talk explaining how to make open-source projects, which people want to use from my perspective.

Below, you can find slides from my presentation. Thank you all for the attendance, interesting questions and organizers for inviting me. I hope you learned something new.
Of course, any constructive feedback for this talk will be appreciated :).


JDD 2016 Conference

2016-08-21 Conferences, Java No comments


This year in the beginning of the October is highly recommended to be in Kraków, Poland in order to attend JDD (Java Developers Days) Conference.

jdd_logoJDD is an unusual conference. You can hear the presentations of both experienced people and those who are starting their adventure in the IT industry. You meet speakers from Poland and all around the world. There’s also a wide range of presentation topics concerning not only technical trends and practices but also work methodology, communication, how to talk with people, etc. what has the same importance as coding proficiency.

JDD_4  JDD_1  JDD_7

Besides the presentations, you can meet a lot of interesting people from IT industry in Poland and abroad including programmers, QAs, managers, leaders, etc. There’s a great possibility to establish new contacts and meet old friends. If you are looking for new job opportunities or want to make a market research, you can also do that because there’s a lot of companies looking for new employees. I’ve attended this conference in the last years and I can tell that atmosphere is really great and you can learn a lot. Moreover, Kraków is a very nice city to spend some time, visit the old town, sightseeing, and go to the pubs in the night. Not to mention, there’s party after conference days :-).


Discount for the blog readers!

All blog readers have 15% discount for the conference tickets with the code JDD_wittblog. I hope, it’ll encourage you to fill in the registration form.

See you at the conference!

Reactive Live Coding during GDG DevFest 2015 in Poland

2015-11-29 Android, Conferences, Google, Java, RxJava 2 comments

I was asked to be a speaker during GDG DevFest 2015 conference in Warsaw, Poland. Of course, I accepted this invitation and prepared presentation titled “Reactive Live Coding”. Presentation covered basics of Reactive Programming, RxJava and RxAndroid. Besides my talk I’ve done live coding to show how to use mentioned libraries and basics principles of Reactive Programming in real life. I had only 20 minutes for all of that, so my time-box was very limited. Being a speaker at conference was really interesting and challenging experience, which I haven’t had before. Moreover, I could meet a lot of interesting people and hear very inspiring talks covering different topics. You can check activity from conference by browsing #devfest15pl hashtag on Twitter and Facebook event. You can also check official website of the conference at

Slides from my presentation are available below.

Source code of the exemplary Android app shown and partially coded during the presentation is available at

Picture documenting part of my short talk made by @depodefi can be found below.


GDG DevFest organizers have done really good job and I can definitely recommend this conference to anyone interested in new IT technologies.

Devoxx Poland 2015 – conference summary

2015-06-29 Conferences, Java No comments

This year, for the first time the Devoxx conference was held in Poland. There were plenty of lectures and experts to learn from.

On technical blog of Future Processing, you can find Devoxx Conference summary:

In my opinion, one of the most interesting talks was prepared by Venkat Subrananiam and titled: “Get Past the Syntax, The Real Scare is in the Semantics”. That’s why I presented my thoughts connected with this presentation. Please, check out mentioned article to find more information about this and other topics.

Quality Excites 2015 – Call For Papers

2015-03-12 Conferences No comments

Quality Excites (QE) is a Polish nationwide conference on software quality dedicated to the professionals who use the newest technologies and the best practices. It’s dedicated to people who want to exchange knowledge and experience in order learn about innovative concepts that could improve the quality of developed products.

If you want to become a speaker at Quality Excites, you can send your application by April 10, 2015.

Conference will take place in Gliwice, Poland on 30th of May 2015.