Name: Datafaker, code puzzles and the Java immutable record
Start: 2025-01-14T17:00:00+01:00
End: 2025-01-14T20:00:00+01:00
Location: ING Leeuwarden

Interested in optimising test data with Datafaker, code competitions and immutability with records? Come join us on Tuesday January 14th with Elias Nogueira covering Datafaker, and two 15 minute lightning talks by Guus Klinkenberg on the opportunities of coding competitions and Johan Hutting on immutability with the record type we received in Java 16.

The venue opens at 16:30, the first talk will start at 17:00. In between the sessions there will be drinks and dinner.

🇬🇧**Datafaker: the most powerful fake data generator library** by **Elias Nogueira (Backbase)**
Data generators in software testing play a critical role in creating realistic and diverse datasets for testing scenarios. However, they present challenges, such as ensuring data diversity, maintaining quality, facilitating validation, and ensuring long-term maintainability.

While many engineers are familiar with these challenges, they often resort to non-specialized tools like the RandomStringUtils class from Apache Commons or the Random class, concatenating fixed data with it. This approach lacks scalability and may not yield a valid dataset.

Thankfully we have DataFaker, a library for Java and Kotlin to generate fake data, based on generators, that can be very helpful when generating test data to fill a database, to generate data for a stress test, or to anonymize data from production services.

With practical examples, you will learn how to generate data based on:
\- different or multiple locales
\- random enum values
\- different generators like address\, code \(books\)\, currency\, date and time\, finance\, internet\, measurement\, money\, name\, time\, and others
\- custom \(data\) providers
\- sequences \(collections and stream\)
\- date formats
\- expressions
\- transformations
\- unique values

In the end, patterns for generating better data like the Test Data Factory will also take place to add more control to the data generation.

🇬🇧**From Puzzles to Proficiency: The Opportunities of Coding Competitions** by **Guus Klinkenberg (ING)**
For as long as we know, we have been competing. Arenas were built by the Romans to compete. Put to two kids in a room with just a stone, and they will start a completion about the silliest thing they can do with that stone. Humans are inherently competitive. However, the work we do is mostly about market outcome, and the outcome is not entirely based on skills or how good we are at using our tools. Programming competitions like Advent of Code or hackathons are a nice environment to experiment with tools and technologies while gaining new or improving skills and insights. And at the same time, you connect with colleagues or new people.

In this talk, we first dive into why these competitions can be fun, and how we can benefit from events like this. Next, we look into my experience while organizing various programming competitions. This will include some examples, takeaways and maybe a blunder or two, which will help you participate or organize a competition!

🇬🇧**The record: migrate to immutability** by **Johan Hutting (ING)**
JEP-395 in Java 16 brought us records to store and model immutable data, allowing developers to replace POJO's in many cases.
In this lightning talk we'll cover the benefits of records, when to migrate towards them and when to retain POJO's. And how does the Lombok @Value fit into all of this?

We'll also cover the various ways to migrate your old code, or prepare them for a later migration easing the amount of work while gaining the maximum amount of benefits from records.

**About the speakers**
**Elias Nogueira** is a Java Champion, Oracle ACE, JavaMagazine NL editor, and Senior Principal Software Engineer working at Backbase.

**Guus Klinkenberg** is a software engineer at ING and presented at TeqNation and J-Fall this year. While finishing his masters in computing science, he worked at a startup. After a stint in secondment, he started at ING in 2023. He loves to learn, which allows him to keep up with new technology, and enjoys sharing knowledge. In his spare time, he tries to keep up with science, and volunteer for some IT conferences and communities.

**Johan Hutting** is a software engineer and developer advocate at ING with more than 15 years of experience designing, developing and maintaining Android, Java SE/EE and Spring applications. Strong focus on getting things done with the Agile mindset. Love to share knowledge on the latest Java language, EE and Spring improvements by giving workshops and talks as well as participating in them.

Johan Hutting

JUG Noord

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Datafaker, code puzzles and the Java immutable record

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Datafaker, code puzzles and the Java immutable record

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