16/11/21

Delivery Hero 💚 Droidcon

By Miloš Marinković

As you probably noticed, Droidcon 2020, like most other conferences last year, never happened. That was a long, sad year with very little community activity. Things were changing for the better in 2021, so the Droidcon organizers decided to give it a shot and hold the beloved conference this October. Of course, we wanted to be there to support our big happy Android community. And wow, it was awesome!

What did we get up to at Droidcon?

Most importantly, we wanted to meet the attendees! With over 1200 conference attendees, and more than 300 visitors to our booth, we had a unique opportunity to connect directly with the community. We are lucky to have such talented people around us!

Some of our visitors were surprised to learn that Delivery Hero operates under different names in some countries. This is just one of the many exciting things our global tech team has to offer. Below are our most popular brands around the world 🌍: 

We had the opportunity to showcase our restaurant app on a real device with print capability – the device we deliver to well over 600 thousand of our vendors across the globe.

Other than connecting with the visitors directly, we also visited some of the talks throughout the conference.

Our favorites are listed below:

Day 1  🗣

  • Filip and Márton talking about Building a Chat SDK Using Jetpack Compose
  • Marcin talking about Efficient Kotlin
  • Nelson talking about Android Cache Fix plugin and Gradle support

Day 2  📣

  • Nicola talking about Detekt – State of the Union
  • Mario talking about Printed Circuit Boards and Android (A Love Story)
  • Volker and Alexey talking about Scaling App development

Day 3  😌

  • Chet talking about Comedy in IT
  • Tautvydas, Miriam, Erik and Tobias discussing The future of work
  • Marco talking about Introducing Kotlin Multiplatform in an existing project

We look forward to sharing our knowledge with you at next year’s Droidcon!

Tech Challenge TV

It’s humbling to say that more than 300 people visited us at the Delivery Hero booth this year. Some of them were just picking up the Hero SWAG, some bumped into us by chance and wanted to chat, some were our current and former colleagues, and others were genuinely interested in what we do and why we are successful in the delivery business.

However, the most interesting thing for most of our visitors was probably our Tech Challenge TV. Each day of the conference, we had a small set of Kotlin challenges prepared and curated by our tech team. Visitors then had a few minutes to think about the challenge and choose an answer from a multiple-choice question. After much discussion, compilation, thought, and laughter – we announced the correct answers, and invited visitors to come back the next day and continue! 👩‍💻 👨‍💻

Think you can do better? 

Here is a sneak peek at our most popular challenges!

Challenge 1.1

Choose an answer:

(a) crash/exception (wrong pin)

(b) crash/exception (number format)

(c) 10,10

(d) compile error

Challenge 2.1

Choose an answer:

(a)   crash/exception: index out of bounds

(b)   compile error

(c)   6

(d)   3

(e)   12


Ready for the solutions? 🧠

Challenge 1.1

(d) compile error

Extension functions are compiled into static constructs that have the receiver class as an argument. Consequently, an extension function cannot access any private properties of the receiver class (such as money in this particular example) – and therefore the program outputs an error at compile time.

Challenge 2.1

(d) 3

We need to take a few things into consideration:

  1. Index of the first character in Kotlin is zero
  2. There’s a space in the middle of the input string

With that in mind, we have indices:

(“A”:0) (“B”:1) (“C A”:-1) (“B”:1) (“C”:2)

Sum of which is 0+1-1+1+2


So, were these challenges too difficult?

Yes, probably… but they were also exciting! 🎉 They were not meant to be solved in seconds, and the solution did not have to be correct either. It was a game we all participated in, and hopefully learned something new and interesting from! 📚

Droidcon was an absolute blast, and we had so much fun meeting you all. What made it even more special was the fact that it had been so long since we had been at a ‘real life’ conference! We are already looking forward to next year, and preparing our 2022 Tech Challenge Questions! Until then, we will see you around. 👋


Thank you, Milos, for sharing your experience at Droidcon Berlin 2021 with us! It is so exciting to be able to attend offline events again! 

As always, we are still hiring, so check out some of our latest openings, or join our Talent Community to stay up to date with what’s going on at Delivery Hero and receive customized job alerts!