The 1BRC - One Billion Row Challenge by Gunnar Morling kept countless programmers busy in January 2024. How fast can you process a CSV file with one billion lines? Well, as it turns out, you can do it in almost no time. 
While the winning entries use Graal, Unsafe, SWAR, custom hashing, and more, this talk will instead take the audience on the first 80% of the journey. These 80% use simple and plain Java, but that still guarantees a fun ride. We will go step by step from a naive first 130-second approach to a 10-second solution. 
Along the way, we will explore the performance impact of our changes, the reasons for the difference, and the tools to get the data we need to move forward. All of this will be done using Java 21.
As a bonus, we will see the Java 17 performance in comparison. Finally, we will examine the impact of proper error handling, as 1BRC set up rules made it possible to skip all error handling.