Hands-On Spring Boot Tutorials for Beginners: Step-by-Step Guide

 Introduction

Spring Boot is the most popular framework for building Java backend applications today. It removes complex configuration and helps beginners start building real applications quickly.

If you are new to Spring Boot or Java backend development, this hands-on tutorial will guide you from zero to a working REST API, using simple examples and real-world practices.

In this blog, you will learn:

• How Spring Boot works

• How to create your first Spring Boot project

• How to build REST APIs

• How to connect a database

• How to test and run your application

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Prerequisites

Before starting, make sure you have:

• Basic knowledge of Java

• JDK 17 or later installed

• An IDE (IntelliJ IDEA / Eclipse / VS Code)

• Maven or Gradle

No prior Spring knowledge is required.

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Step 1: What Is Spring Boot?

Spring Boot is a framework that helps you build standalone, production-ready Java applications with minimal configuration.

Key advantages:

• Embedded server (no Tomcat installation)

• Auto-configuration

• Easy dependency management

• Fast development

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Step 2: Creating Your First Spring Boot Project

The easiest way to start is using Spring Initializr.

Project settings:

• Project: Maven

• Language: Java

• Spring Boot version: Latest stable

• Group: com.example

• Artifact: demo

• Dependencies:

  • Spring Web

After generating the project, open it in your IDE.

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Step 3: Understanding the Project Structure

src/main/java
 └── com.example.demo
     └── DemoApplication.java

src/main/resources
 └── application.properties

• DemoApplication.java → main entry point

• application.properties → configuration file

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Step 4: Creating Your First REST Controller

Create a new class:

@RestController
@RequestMapping("/api")
public class HelloController {

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

Run the application and open:

http://localhost:8080/api/hello

🎉 Congratulations! You have created your first Spring Boot API.

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Step 5: Using application.properties

Spring Boot uses application.properties to manage configuration.

Example:

server.port=8081
spring.application.name=demo-app

Restart the application and access it on the new port.

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Step 6: Connecting to a Database (JPA)

Add dependency:

• Spring Data JPA

• H2 / PostgreSQL / MySQL

application.properties example:

spring.datasource.url=jdbc:h2:mem:testdb
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

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Step 7: Creating Entity and Repository

Entity:

@Entity
public class User {

    @Id
    @GeneratedValue
    private Long id;
    private String name;
}

Repository:

public interface UserRepository extends JpaRepository<User, Long> {
}

Spring Boot automatically creates database tables.

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Step 8: Creating Service and Controller Layer

Service:

@Service
public class UserService {

    private final UserRepository repository;

    public UserService(UserRepository repository) {
        this.repository = repository;
    }

    public List<User> getAllUsers() {
        return repository.findAll();
    }
}

Controller:

@RestController
@RequestMapping("/users")
public class UserController {

    private final UserService service;

    public UserController(UserService service) {
        this.service = service;
    }

    @GetMapping
    public List<User> getUsers() {
        return service.getAllUsers();
    }
}

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Step 9: Testing Your Spring Boot Application

Spring Boot supports testing using JUnit and Mockito.

Example:

@SpringBootTest
class DemoApplicationTests {

    @Test
    void contextLoads() {
    }
}

Testing ensures your application works as expected.

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Step 10: Running the Application

You can run your app:

• From IDE

• Using Maven:

mvn spring-boot:run

• Or as a JAR:

java -jar target/demo.jar

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Common Beginner Mistakes

❌ Forgetting @RestController
❌ Missing dependencies
❌ Wrong package structure
❌ Hardcoding configuration values
❌ Not separating controller, service, repository

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Best Practices for Beginners

✔ Follow layered architecture
✔ Use application.yml or application.properties
✔ Keep controllers thin
✔ Handle exceptions globally
✔ Use logs instead of System.out.println

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What to Learn Next?

After this tutorial, you should explore:

• Spring Security (JWT, OAuth2)

• Spring Boot microservices

• Spring Cloud basics

• Dockerizing Spring Boot apps

• Cloud deployment (Azure / AWS)

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Conclusion

Spring Boot makes Java backend development simple, fast, and beginner friendly. By following hands-on tutorials and building small projects, you can quickly gain confidence and move toward real-world enterprise applications.

If you are serious about Java backend development, Spring Boot is the best place to start.

💼 Professional Support Available

If you are facing issues in real projects related to enterprise backend development or workflow automation, I provide paid consulting, production debugging, project support, and focused trainings.

Technologies covered include Java, Spring Boot, PL/SQL, Azure, and workflow automation (jBPM, Camunda BPM, RHPAM).

📧 Contact: ishikhanirankari@gmail.com | info@realtechnologiesindia.com

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