Demos & examples

See every principle and capability, live.

Each demo is mapped 1:1 to a data-mesh principle — domain ownership, data as a product, self-serve platform, federated computational governance — and to the Quarkus capability it exercises. The runnable examples/ tree and all 19 demos/*.sh scripts are in the repo today — every card below links straight to the script and the service it exercises.

Run them all

demos/walkthrough.sh is the five-act presenter orchestrator that runs the full set back to back. For the complete demo-by-demo matrix (prereqs, opt-in profiles, what each one asserts), see demos/README.md ↗. First time here? Start with setup & prerequisites.

Demos by principle

Domain ownership & data as a product

Each domain service — order, inventory, payment, shipping, notification, review — owns its data, its API surface, and its operational lifecycle.

Domain ownership · Panache + REST

Order-service walking skeleton

demo-order.sh — build, deploy, REST round-trip against a Panache-backed Postgres entity in examples/order-service.

Domain ownership · gRPC

Cross-service gRPC

demo-grpc.sh — order-service calls inventory-service over quarkus-grpc. Proves domain isolation with clear API boundaries.

Data as a product · GraphQL

Federated read layer

demo-graphql.sh — the examples/graphql-gateway SmallRye GraphQL gateway stitches REST and gRPC data products into one composed query.

Self-serve platform

Self-serve platform · Kafka

Kafka messaging with Reactive Messaging

demo-kafka.sh — order-service publishes order.placed; notification-service consumes it via Quarkus Reactive Messaging, confirmed on the wire through Apicurio.

Self-serve platform · KEDA

Scale-from-zero autoscaling

demo-keda-kafka.sh and demo-keda-http.sh — Kafka consumer-lag and HTTP-concurrency scaling on the local Kubernetes cluster (opt-in — requires the Istio/KEDA/Strimzi/CloudNativePG cluster from scripts/bootstrap.sh).

Self-serve platform · dev loop

Continuous testing & Dev Services

demo-continuous-testing.sh — live reload, continuous testing, and Testcontainers-backed Dev Services as platform capabilities.

Self-serve platform · Panama FFM

Native calls without JNI

demo-panama.sh — a JBang script (demos/jbang/PanamaFfm.java) calls libc getpid() and strlen() through the Foreign Function & Memory API (JEP 454). No JNI, no C glue, no native build (Linux).

Federated computational governance

Federated governance · Camel

Camel EIPs on Quarkus

demo-camel-integration.sh — a Camel route in examples/ai-mcp-service transforms and routes a message end-to-end through its EIPs.

Federated governance · langchain4j + MCP

AI tool routes

demo-ai-mcp.sh — a Camel route in examples/ai-mcp-service exposes an order-lookup tool over MCP; see also demo-ai-triage.sh and demo-orchestration-styles.sh for the Kafka-choreography / Camel-orchestration / Quarkus-Flow-orchestration comparison.

Federated governance · OpenTelemetry

End-to-end tracing

demo-tracing.sh — a request produces the expected trace-span shape in the otel-lgtm stack (Tempo), spanning multiple data products.

Quarkus vs. Spring Boot

One runnable Spring Boot twin service, examples/spring-boot-compare, ships alongside its Quarkus counterpart for a real side-by-side comparison — startup time, memory footprint, and native-image build (see scripts/compare-quarkus-springboot.sh).

Running a demo

Every demo assumes the local Docker Compose stack (Kafka, Postgres, Apicurio, the observability stack) is running. See setup & prerequisites for the toolchain, then:

cp .env.example .env
docker compose up -d
./demos/demo-order.sh        # or any other demos/demo-*.sh
./demos/walkthrough.sh       # run the full five-act set

Some demos are opt-in — AI/MCP demos need docker compose --profile ollama up -d, the native demo needs a GraalVM/Mandrel build, and the KEDA demos need the local Kubernetes cluster from scripts/bootstrap.sh. See demos/README.md ↗ for the full prereqs-by-demo matrix.