Getting Started with Spring Boot -

Spring Boot is an extension of the Spring Framework that simplifies the process of building stand-alone, production-grade Spring applications. It removes the need for extensive XML configuration and boilerplate setup that traditional Spring applications required.

Why Spring Boot is used:

Auto-configuration – automatically configures Spring and third-party libraries based on the dependencies present in the project, reducing manual setup.
Embedded servers – ships with embedded Tomcat/Jetty/Undertow, so applications can run as standalone JARs without deploying to an external server.
Starter dependencies – curated dependency bundles (e.g., spring-boot-starter-web, spring-boot-starter-data-jpa) that pull in compatible library versions automatically.
Production-ready features – built-in support for metrics, health checks, and externalized configuration via Spring Boot Actuator.
No XML configuration – uses Java-based and annotation-based configuration instead of verbose XML files.
Rapid development – lets developers go from zero to a running REST endpoint in minutes.

How it simplifies Spring development:

Traditional Spring required manually wiring beans, configuring a DispatcherServlet, setting up a web server, and managing dependency versions by hand. Spring Boot’s @SpringBootApplication annotation combines @Configuration, @EnableAutoConfiguration, and @ComponentScan into one entry point, and the embedded server means there’s nothing extra to install or deploy — you just run the JAR.

Hands-on Experiment: Create a Basic Spring Boot Application with a “Hello Spring Boot” Endpoint

To create a simple Spring Boot application and expose a REST endpoint that returns a “Hello Spring Boot” message.

Software/Tools Required

Java JDK 17 (or 11+)
Spring Boot 3.x (or 2.7.x)
Maven (or Gradle)
IDE (IntelliJ IDEA / Eclipse / STS / VS Code)
Browser or Postman (to test the endpoint)

The following steps are involved in developing this hands-on experiment.

Step 1: Generate the Project

Step 2: Project Structure

Step 3: pom.xml (key dependency)

Step 4: application.properties

Step 5: Main Application Class

Step 6: REST Controller

Step 7: Run the Application

Step 8: Test the Endpoint

Step-by Step Application Development

Step 1: Generate the Project

Use Spring Initializr with:

Project: Maven
Language: Java
Spring Boot version: 3.2.x (latest stable)
Group: net.codejava
Artifact: hello-spring-boot
Packaging: Jar
Java version: 17
Dependency: Spring Web

Download the generated ZIP and extract/import it into your IDE.

Step 2: Project Structure

Step 3: pom.xml (key dependency)

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
This starter pulls in Spring MVC, an embedded Tomcat server, and Jackson for JSON handling — everything needed for a REST endpoint.Code language: HTML, XML (xml)

Step 4: application.properties

server.port=8080

spring.application.name=hello-spring-boot

Step 5: Main Application Class

package net.codejava.hello_spring_boot;

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

@SpringBootApplication
public class HelloSpringBootApplication {

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

}

Step 6: REST Controller

package net.codejava.hello_spring_boot;

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

@RestController
public class HelloController {

    @GetMapping("/hello")
    public String sayHello() {
        return "Hello Spring Boot!";
    }
}

@RestController = @Controller + @ResponseBody, so the return value is written directly to the HTTP response body (as plain text/JSON) rather than resolved to a view.
@GetMapping(“/hello”) maps HTTP GET requests at /hello to this method.

Step 7: Run the Application

click on the HelloSpringBootApplication.java and Run the HelloSpringBootApplication.java

Step 8: Test the Endpoint

Open a browser or use Postman:

http://localhost:8080/hello