Deployment

Spring Boot Fat JAR

Spring Boot produces a fat JAR that contains all dependencies. No need to install the framework separately.

Build the fat JAR:

# Maven
mvn clean package

# or skip tests
mvn clean package -DskipTests

# Gradle
./gradlew build

The JAR file is located in target/ (Maven) or build/libs/ (Gradle):

target/
├── myapp-1.0.0.jar      ← Fat JAR (executable)
├── myapp-1.0.0.jar.original  ← Original JAR (without dependencies)
└── myapp-1.0.0.jar.sha1

Running the Fat JAR

java -jar target/myapp-1.0.0.jar

# With a profile
java -jar target/myapp-1.0.0.jar --spring.profiles.active=prod

# With a custom port
java -jar target/myapp-1.0.0.jar --server.port=9090

# With environment variables
java -jar target/myapp-1.0.0.jar \
  --spring.datasource.url=jdbc:postgresql://db:5432/myapp \
  --spring.datasource.username=postgres \
  --spring.datasource.password=secret

Docker

Dockerfile

# Multi-stage build
FROM eclipse-temurin:21-jdk-jammy AS build
WORKDIR /app
COPY . .
RUN mvn clean package -DskipTests

FROM eclipse-temurin:21-jre-jammy
WORKDIR /app
COPY --from=build /app/target/*.jar app.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "app.jar"]

Build and run:

# Build the image
docker build -t myapp:1.0.0 .

# Run the container
docker run -d -p 8080:8080 --name myapp myapp:1.0.0

# Check the logs
docker logs -f myapp

# Stop the container
docker stop myapp

Docker Compose

# docker-compose.yml
version: '3.8'

services:
  app:
    build: .
    ports:
      - "8080:8080"
    environment:
      - SPRING_PROFILES_ACTIVE=docker
      - SPRING_DATASOURCE_URL=jdbc:postgresql://db:5432/myapp
      - SPRING_DATASOURCE_USERNAME=postgres
      - SPRING_DATASOURCE_PASSWORD=secret
    depends_on:
      db:
        condition: service_healthy
    restart: unless-stopped

  db:
    image: postgres:16-alpine
    environment:
      - POSTGRES_DB=myapp
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=secret
    ports:
      - "5432:5432"
    volumes:
      - pgdata:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 5s
      timeout: 5s
      retries: 5

volumes:
  pgdata:

# Build and run all services
docker-compose up -d

# Rebuild
docker-compose up -d --build

# Stop everything
docker-compose down

# Stop and remove volumes
docker-compose down -v

Deploying to the Cloud

Railway

# Install the Railway CLI
npm install -g @railway/cli

# Log in
railway login

# Initialize the project
railway init

# Deploy
railway up

Or connect a GitHub repository directly from the Railway dashboard.

Render

1. Create an account at render.com
2. Connect a GitHub repository
3. Choose Web Service
4. Configure:
5. Build Command: mvn clean package -DskipTests
6. Start Command: java -jar target/*.jar
7. Port: 8080
8. Deploy

Fly.io

# Install flyctl
curl -L https://fly.io/install.sh | sh

# Log in
fly auth login

# Initialize
fly launch

# Deploy
fly deploy

Environment Variables

Always use environment variables for secrets in production:

export SPRING_PROFILES_ACTIVE=prod
export SPRING_DATASOURCE_URL=jdbc:postgresql://db-host:5432/myapp
export SPRING_DATASOURCE_USERNAME=postgres
export SPRING_DATASOURCE_PASSWORD=mysecretpassword
export JWT_SECRET=myjwtsecretkey123

# application.properties still needs placeholders
spring.datasource.url=${SPRING_DATASOURCE_URL}
spring.datasource.username=${SPRING_DATASOURCE_USERNAME}
spring.datasource.password=${SPRING_DATASOURCE_PASSWORD}

Health Checks for Production

# Enable the health endpoint for the load balancer
management.endpoints.web.exposure.include=health,info
management.endpoint.health.show-details=when-authorized

# Health check
curl http://localhost:8080/actuator/health

Deployment Checklist

Post-Deployment Monitoring

# Check that the application is running
curl http://your-app.onrender.com/actuator/health

# Check metrics
curl http://your-app.onrender.com/actuator/metrics

# Check logs
docker logs -f myapp

With proper deployment, your application is ready for users. In the final chapter, we'll look at the Spring Boot Cheatsheet as a quick reference.