First Spring Boot Example

https://github.com/spring-boot-tutorials/spring-boot-example

In this article we will create our very first Spring Boot application

Create Initial Code Base

Go to https://start.spring.io/
Click Add Dependencies, search for Spring Web, then add
Click Generate

Modify Code Base

Create a new file under src/main/java/com/example/demo/controller/MainController.java with the following contents

@RestController
@RequestMapping("/")
public class MainController {

    @GetMapping("/")
    public String main() {
        return "Hello, World!";
    }
}

Run Application

Open terminal at project root and execute the following:

mvn spring-boot:run

There should be no errors and the output should look something like

...
2025-07-28T17:45:31.524-05:00  INFO 6095 --- [demo] [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port 8080 (http) with context path '/'
2025-07-28T17:45:31.530-05:00  INFO 6095 --- [demo] [           main] com.example.demo.DemoApplication         : Started DemoApplication in 0.814 seconds (process running for 0.953)

Verify Endpoint

In a browser, goto http:/localhost:8080/ and you should see Hello, World!