Event Modeling and Event Sourcing with AI - Building an Java App Live

In this live coding session, I sit down with ‪@AdamDymitruk‬, the creator of Event Modeling, to build a real Java application with Event Sourcing and AI. Most backend systems store the latest state. In this session, we store the history of what actually happened. Together, we model and build a food delivery app inspired by systems like Uber Eats and DoorDash. Orders move through the system as immutable business events such as OrderPlaced, PreparationStarted, CourierAssigned, and OrderDelivered. Instead of updating database rows, we rebuild application state from event streams. You will see how Event Modeling works in practice, how Event Sourcing changes backend design, and how AI can help speed up real software development without hiding the architecture behind frameworks or magic abstractions. We build the application live in Java using Spring Boot, Vaadin and PostgreSQL. Along the way, we design aggregates, implement command handling, replay events to reconstruct state, and create read models from projections. We also discuss Domain Driven Design, CQRS concepts, and the tradeoffs behind event driven systems. This session is aimed at Java developers, backend engineers, software architects, and anyone curious about Event Sourcing, Event Modeling, DDD, or AI assisted development. No slides. No toy examples. Just real architecture, real code, and real design discussions. Tech stack: Java, Spring Boot, Vaadin, PostgreSQL, Maven. Timestamps: 00:00 Introduction 17:11 Event Sourcing 30:36 Starting Event Modeling 01:18:07 Using AI to Implement the Event Model 01:27:39 Video from old AI implementation 01:31:14 Test base application 01:36:57 Using GitHub Copilot for implementation 01:37:47 Adams completed example 01:52:15 Showing the running food delivery demo 01:56:17 Back to Adams completed example 02:19:16 Looking at the Java Application 02:30:00 Conclusion #java #eventsourcing #eventmodeling #ddd #cqrs #springboot #softwarearchitecture #backend #livecoding #ai