Project Setup & Bootstrapping

• Creating a project, understanding the structure, running in dev mode.

1. What are the ways to create a Quarkus project?

Answer:
There are three main approaches:

Option A – Quarkus CLI (recommended):

# Install CLI (once)
curl -Ls https://sh.jbang.dev | bash -s - trust add https://repo1.maven.org/maven2/io/quarkus/quarkus-cli/
curl -Ls https://sh.jbang.dev | bash -s - app install --fresh --force quarkus@quarkusio

# Create project
quarkus create app com.example:my-app \
  --extension='rest,hibernate-orm-panache,jdbc-postgresql'

Option B – Maven plugin:

mvn io.quarkus.platform:quarkus-maven-plugin:3.9.0:create \
  -DprojectGroupId=com.example \
  -DprojectArtifactId=my-app \
  -Dextensions="rest,hibernate-orm-panache"

Option C – Web UI:
Visit code.quarkus.io, select extensions, and download a ZIP.

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2. What does the generated project structure look like?

Answer:

my-app/
├── src/
│   ├── main/
│   │   ├── java/com/example/          # Application code
│   │   │   └── GreetingResource.java  # Sample REST endpoint
│   │   ├── resources/
│   │   │   ├── application.properties # All configuration here
│   │   │   └── META-INF/resources/    # Static files (index.html, etc.)
│   │   └── docker/                    # Dockerfiles (JVM + native)
│   └── test/
│       └── java/com/example/          # Tests
├── pom.xml                            # Maven build
└── .mvn/                              # Maven wrapper

Key files:

• application.properties – Single config file for all settings (DB, HTTP port, etc.).
• pom.xml – Declares the quarkus-bom (bill of materials) — no version management needed per extension.

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3. How do you run a Quarkus application in development mode?

Answer:

quarkus dev
# or
./mvnw quarkus:dev

Dev mode provides:

• Live reload – Changes to Java, config, and templates are picked up automatically without restart.
• Dev UI – Available at http://localhost:8080/q/dev — shows all extensions, config, endpoints, and more.
• Continuous testing – Tests run in the background on file save.
• Dev Services – Automatically starts Docker containers for databases, Kafka, etc. — zero config needed in dev.

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4. What are Dev Services and how do they help?

Answer:
Dev Services automatically spin up external dependencies (databases, Kafka, Redis, etc.) using Testcontainers when you run quarkus dev — without any configuration.

For example, if you add quarkus-jdbc-postgresql but don’t configure quarkus.datasource.jdbc.url, Quarkus starts a PostgreSQL Docker container and wires it automatically.

Requirements:

• Docker must be running.
• No quarkus.datasource.jdbc.url set (absence triggers Dev Services).

# Dev Services kicks in automatically — no config needed in dev
# For production, set explicitly:
%prod.quarkus.datasource.jdbc.url=jdbc:postgresql://prod-host:5432/mydb

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5. What is the application.properties profile system?

Answer:
Quarkus uses named profiles to manage config per environment. The default profiles are:

Profile	Activates when
dev	Running quarkus dev
test	Running tests
prod	Building the final artifact

Prefix any property with %profile. to scope it:

# Active in all profiles
quarkus.http.port=8080

# Only in prod
%prod.quarkus.datasource.jdbc.url=jdbc:postgresql://prod:5432/db
%prod.quarkus.log.level=WARN

# Only in dev
%dev.quarkus.log.level=DEBUG

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6. How do you build and run a Quarkus application for production?

Answer:

JVM build (fast build, standard JVM):

./mvnw package
java -jar target/quarkus-app/quarkus-run.jar

Native build (slow build, fast startup):

./mvnw package -Dnative
# or using a container build (no local GraalVM needed):
./mvnw package -Dnative -Dquarkus.native.container-build=true
./target/my-app-1.0-runner

Docker image:

# JVM
docker build -f src/main/docker/Dockerfile.jvm -t my-app:jvm .
# Native
docker build -f src/main/docker/Dockerfile.native -t my-app:native .

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Summary Table

Task	Command
Create project	quarkus create app com.example:my-app
Run in dev mode	quarkus dev
Add extension	quarkus ext add <name>
Build JVM jar	./mvnw package
Build native	./mvnw package -Dnative
Open Dev UI	http://localhost:8080/q/dev