The Quarkus deep-dive
What Quarkus provides: the extensions, the dev loop, startup options, and the two orchestration engines this project runs alongside Kafka choreography.
A Quarkus capability tour
Twelve Quarkus and JDK 25 capabilities, each anchored to code or a demo script in this project: Panache, gRPC, GraphQL, Reactive Messaging, WebSockets.Next, Vert.x reactive and imperative execution, continuous testing, native image and the JDK AOT cache, OIDC, JBang, and Panama FFM.
Quarkus vs. Spring Boot
The same order-service data product, rebuilt as a Spring Boot twin, measured side by side on the JVM — startup time and resident memory, and what is and isn't being compared.
Orchestration styles: choreography vs. two kinds of orchestration
Three coordination engines over the same shipping/order domain (Kafka choreography, a Camel route, and a declarative Quarkus Flow workflow) and when decentralized reaction beats a named coordinator.
AI-assisted rules triage: Ollama classifies, Drools decides
An LLM extracts structured fields from an order; a deterministic Drools rule set makes the business decision. The chapter also covers where in-process langchain4j tool-calling works and where it does not on this stack.