Spring Boot Hello World REST API Example

In this post, we will build a simple hello world REST API using Spring boot.

Spring Boot is an opinionated framework that helps developers build Spring-based applications quickly and easily. The main goal of Spring Boot is to quickly create Spring-based applications without requiring developers to write the same boilerplate configuration again and again.

Let's create a Spring boot application step by step.

1. Create Spring Boot Project

Spring Boot provides a web tool called https://start.spring.io to bootstrap an application quickly. Just go to https://start.spring.io and generate a new spring boot project.

Use the below details in the Spring boot creation:

Project Name: springboot-first-app

Project Type: Maven

Choose dependencies: Spring Web

Package name: com.springboot.app

2. Maven Dependencies

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
		<relativePath/> <!-- lookup parent from repository -->
	<description>Spring Boot First Application</description>




3. Spring Boot Hello World REST API

Let's create a HelloWorldController class and the below code to it:
package com.springboot.first.app;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

public class HelloWorldController {
	// GET HTTP Method
	// http://localhost:8080/hello-world
	public String helloWorld() {
		return "Hello World!";
  • The above code uses Spring 4’s new @RestController annotation, which marks the class as a controller where every method returns a domain object instead of a view. It’s shorthand for @Controller and @ResponseBody rolled together.
  • @GetMapping annotation for mapping HTTP GET requests onto specific handler methods. Specifically, @GetMapping is a composed annotation that acts as a shortcut for @RequestMapping(method = RequestMethod.GET).

4. Run Spring Boot Application

The below class SpringbootFirstAppApplication is the entry point that sets up the Spring Boot application. The @SpringBootApplication annotation enables auto-configuration and component scanning.

package com.springboot.first.app;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

public class SpringbootFirstAppApplication {
	public static void main(String[] args) {
		SpringApplication.run(SpringbootFirstAppApplication.class, args);

Run spring boot application from the IDE:

From your IDE, run the SpringbootFirstAppApplication.main() method as a standalone Java class that will start the embedded Tomcat server on port 8080 and point the browser to http://localhost:8080/.

Run spring boot application using the command line:

Just go to the root directory of the application and type the following command to run it -

$ mvn spring-boot:run

The application will start at Spring Boot’s default tomcat port 8080.

Just hit this link in a browser: http://localhost:8080/hello-world. You will able to see the response of this REST API in the browser.