Spring Boot app: from start.spring.io to live, step by step

1. Generate the project

Open start.spring.io → Project Maven, Language Java, Java 17 or 21, add the Spring Web dependency → Generate. Unzip it and open the folder in VS Code or IntelliJ.

2. A first endpoint

@RestController
class HelloController {
  @GetMapping("/")
  String hello() { return "Hello from Cloud Ninza"; }
}

3. Run it locally

./mvnw spring-boot:run        # Windows: mvnw.cmd spring-boot:run
# open http://localhost:8080

4. Push to GitHub

Spring Initializr already adds a .gitignore (it keeps target/ out) and the Maven wrapper mvnw. Push the project.

5. Launch and configure

Launch an app → Java → the same Java version → plan → domain → pay. App settings → Spring Boot (Maven). The start command passes --server.port=$PORT --server.address=127.0.0.1, so no code change is needed for the port. Add SPRING_DATASOURCE_URL, SPRING_DATASOURCE_USERNAME and SPRING_DATASOURCE_PASSWORD with + Add variable → Save all if you use a database.

6. Deploy

Git deployments → connect → Deploy now. The build runs ./mvnw -q -DskipTests package on the server and starts target/*.jar. The JVM heap is set to 70% of your plan's memory automatically.

Go live on your domain

Point the domain's @ and www A records to the IP shown in Domains, wait for Points here, then Issue free SSL → Always use HTTPS → Save changes.

Already have a JAR?

Choose Executable JAR, upload the file as app.jar into web/yourdomain.com/app with the File manager, and press Restart.