JUG.CY, Feb 20 with Aleksandr Pakhomov - Building Your Own Database with Java

Aleksandr Pakhomov — Building Your Own Database in 2 Hours with Java

Ever wondered how radically software development is changing in 2026? How writing real, working systems without an IDE is becoming not just possible but practical? Then this talk is for you.

Join us for a live, experimental session where we’ll build a minimal, working key-value database in Java in just 2 hours — with the help of modern AI tools and agents.

This talk isn’t just theory. It’s a real-world experiment led by someone who lives at the intersection of distributed systems and AI-augmented development: Aleksandr Pakhomov, a committer on Apache Ignite 3 and an active contributor to open-source projects.

Whether you think LLMs are not ready for serious development, believe Java can’t be used to build a database, or have never written a database yourself — this session will challenge expectations and bring clarity. In just one evening, you’ll learn key concepts, see working code, and witness modern development in action.

What exactly will happen

Live coding session where we build a key-value store from scratch using Claude Code as a coding assistant.

Step by step, in front of you:

1. Start with the simplest possible storage — a plain HashMap
2. Add file persistence
3. Evolve the design into an append-only log to achieve O(1) writes
4. Discuss what a database actually consists of: parser, analyzer, execution engine, storage
5. Benchmark our implementation against RocksDB
6. Use flame graphs to visually explain where the performance gap comes from
7. Draw conclusions about how modern AI-assisted development changes the way we approach complex systems

Participation is completely free, but places are limited. Please check in if you plan to attend the meeting; we can't let you into the building if you are not on the list.

Agenda for this evening:

- Doors open at 18:30
- Talk will start at 19:00
- We will have a short break during the talk
- We will have discussions regarding the talk with networking opportunities after.
- We will finish before 22:00 at the office, but nothing can stop us from continuing somewhere in the cozy bar.

About the speaker: Aleksandr Pakhomov (@PakhomovAlexander) is an Apache Ignite 3 committer, works on distributed databases, programming in Java and Rust, prefers Vim, and hosts a software engineering podcast