If you’ve worked with Java web applications, you know the traditional Spring Framework can be powerful but verbose. Configuration files, XML hell, dependency management nightmares—we’ve all been there. Spring Boot changes the game by removing most of this friction, letting you build production-ready applications in minutes instead of hours.
What Makes Spring Boot Different?
Spring Boot isn’t a replacement for Spring—it’s an opinionated layer on top of it. Think of it as Spring with batteries included. The framework makes intelligent assumptions about what you need, provides sensible defaults, and gets out of your way when you want to customize things.
Key advantages:
Auto-configuration: Spring Boot automatically configures your application based on the dependencies you’ve added. Add a database driver, and it configures the connection pool. Add Spring Web, and it sets up an embedded server.
Standalone applications: No need to deploy WAR files to external servers. Your application runs as a simple JAR with an embedded Tomcat, Jetty, or Undertow.
Production-ready features: Health checks, metrics, and monitoring come built-in through Spring Boot Actuator.
Zero XML configuration: Everything can be done through Java annotations and application properties files.
Getting Started: Hello World
Let’s build the classic Hello World REST API to see how simple Spring Boot really is.
Step 1: Create the project
Head to [Spring Initializr](https://start.spring.io) and configure:
- Project: Maven
- Language: Java
- Spring Boot: 3.2.x (latest stable)
- Dependencies: Spring Web
Download and extract the ZIP file.
Step 2: Write the controller
Open the project in your IDE and create a new class:
package com.example.demo;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class HelloController {
@GetMapping("/hello")
public String hello() {
return "Hello, Spring Boot!";
}
}
Step 3: Run the application
Execute the main class (DemoApplication.java) or run:
./mvnw spring-boot:run
That’s it. Open your browser to http://localhost:8080/hello and you’ll see your message. Three files, zero configuration, and you have a working REST API.
Building Something Real: To-Do List API
Now let’s create a simple To-Do List API to demonstrate CRUD operations, data persistence, and best practices.
Step 1: Set up dependencies
Add these to your Spring Initializr or pom.xml:
- Spring Web
- Spring Data JPA
- H2 Database (for development)
- Lombok (optional, reduces boilerplate)
Step 2: Create the entity
package com.example.todo.model;
import jakarta.persistence.*;
import lombok.Data;
@Data
@Entity
@Table(name = "todos")
public class Todo {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column(nullable = false)
private String title;
private String description;
private boolean completed = false;
}
Step 3: Create the repository
Spring Data JPA does the heavy lifting here:
package com.example.todo.repository;
import org.springframework.data.jpa.repository.JpaRepository;
import com.example.todo.model.Todo;
public interface TodoRepository extends JpaRepository<Todo, Long> {
// That's it! CRUD methods are inherited
}
Step 4: Build the service layer
package com.example.todo.service;
import java.util.List;
import org.springframework.stereotype.Service;
import lombok.RequiredArgsConstructor;
import com.example.todo.model.Todo;
import com.example.todo.repository.TodoRepository;
@Service
@RequiredArgsConstructor
public class TodoService {
private final TodoRepository repository;
public List<Todo> findAll() {
return repository.findAll();
}
public Todo findById(Long id) {
return repository.findById(id)
.orElseThrow(() -> new RuntimeException("Todo not found"));
}
public Todo create(Todo todo) {
return repository.save(todo);
}
public Todo update(Long id, Todo todoDetails) {
Todo todo = findById(id);
todo.setTitle(todoDetails.getTitle());
todo.setDescription(todoDetails.getDescription());
todo.setCompleted(todoDetails.isCompleted());
return repository.save(todo);
}
public void delete(Long id) {
repository.deleteById(id);
}
}
Step 5: Create the REST controller
package com.example.todo.controller;
import java.util.List;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.*;
import lombok.RequiredArgsConstructor;
import com.example.todo.model.Todo;
import com.example.todo.service.TodoService;
@RestController
@RequestMapping("/api/todos")
@RequiredArgsConstructor
public class TodoController {
private final TodoService service;
@GetMapping
public List<Todo> getAllTodos() {
return service.findAll();
}
@GetMapping("/{id}")
public Todo getTodoById(@PathVariable Long id) {
return service.findById(id);
}
@PostMapping
@ResponseStatus(HttpStatus.CREATED)
public Todo createTodo(@RequestBody Todo todo) {
return service.create(todo);
}
@PutMapping("/{id}")
public Todo updateTodo(@PathVariable Long id, @RequestBody Todo todo) {
return service.update(id, todo);
}
@DeleteMapping("/{id}")
@ResponseStatus(HttpStatus.NO_CONTENT)
public void deleteTodo(@PathVariable Long id) {
service.delete(id);
}
}
Step 6: Configure the database
Add to src/main/resources/application.properties:
spring.datasource.url=jdbc:h2:mem:tododb
spring.datasource.driverClassName=org.h2.Driver
spring.h2.console.enabled=true
spring.jpa.hibernate.ddl-auto=create-drop
Run the application and test your endpoints with curl or Postman:
# Create a todo
curl -X POST http://localhost:8080/api/todos \
-H "Content-Type: application/json" \
-d '{"title":"Learn Spring Boot","description":"Build awesome apps"}'
# Get all todos
curl http://localhost:8080/api/todos
# Update a todo
curl -X PUT http://localhost:8080/api/todos/1 \
-H "Content-Type: application/json" \
-d '{"title":"Learn Spring Boot","description":"Build awesome apps","completed":true}'
You now have a fully functional REST API with database persistence in under 100 lines of actual business logic.
Practical Tips for Real Projects
Use profiles for different environments
Create separate property files:
application-dev.propertiesapplication-prod.properties
Activate with: --spring.profiles.active=prod
Implement proper error handling
Create a global exception handler:
@RestControllerAdvice
public class GlobalExceptionHandler {
@ExceptionHandler(RuntimeException.class)
@ResponseStatus(HttpStatus.NOT_FOUND)
public Map<String, String> handleNotFound(RuntimeException ex) {
return Map.of("error", ex.getMessage());
}
}
Add validation
Use Bean Validation annotations:
public class Todo {
@NotBlank(message = "Title is required")
private String title;
}
Enable Actuator for monitoring
Add the dependency and access /actuator/health and /actuator/metrics endpoints.
Use DTOs instead of exposing entities
This prevents tight coupling between your database schema and API contracts, and gives you better control over what data is exposed.
Leverage Spring Boot DevTools
Add the devtools dependency for automatic application restart during development. It significantly speeds up the feedback loop.
Spring Boot vs ASP.NET Core: A Quick Comparison
If you’re coming from the .NET world or deciding between ecosystems, here’s how Spring Boot stacks up against ASP.NET Core:
| Feature | Spring Boot | ASP.NET Core |
| Language | Java, Kotlin, Groovy | C#, F# |
| Runtime | JVM | .NET Runtime |
| Project Setup | Spring Initializr | dotnet CLI / Visual Studio |
| Dependency Injection | Built-in Spring Container | Built-in IServiceCollection |
| Web Framework | Spring MVC / WebFlux | MVC / Minimal APIs |
| ORM | Hibernate (JPA), MyBatis | Entity Framework Core |
| Configuration | application.properties / YAML | appsettings.json |
| REST Controller | @RestController, @GetMapping | [ApiController], [HttpGet] |
| Database Migrations | Flyway, Liquibase | EF Migrations |
| Testing | JUnit, Mockito, TestContainers | xUnit, NUnit, Moq |
| Packaging | JAR with embedded server | Self-contained executable or DLL |
| Cloud Support | Excellent (AWS, Azure, GCP) | Excellent (especially Azure) |
| Performance | Very good, improving with GraalVM | Excellent, highly optimized |
| Learning Curve | Moderate (Java verbosity) | Moderate (C# is more concise) |
| Ecosystem | Massive, open-source driven | Growing, Microsoft-backed |
| Licensing | Apache 2.0 (free) | MIT (free) |
Bottom line: Both are production-ready, enterprise-grade frameworks. Choose Spring Boot if you’re invested in the JVM ecosystem or need maximum platform independence. Choose ASP.NET Core if you prefer C#, want tighter Microsoft integration, or need slightly better raw performance.
When to Use Spring Boot
Spring Boot excels at:
- Microservices architectures
- REST APIs and web services
- Traditional web applications with server-side rendering
- Batch processing jobs
- Cloud-native applications
It might be overkill for:
- Simple scripts or CLI tools
- Extremely latency-sensitive applications (though it’s getting better)
- Projects where you need complete control over every dependency
Conclusion
Spring Boot removes the tedious parts of Spring development while keeping all the power. Whether you’re building a quick prototype or a production microservice, it gets you from zero to deployed faster than almost any other JVM framework.
The ecosystem is mature, the documentation is excellent, and the community is huge. If you’re doing Java development in 2025, Spring Boot should be in your toolkit.
Start small with a Hello World, build a CRUD API to understand the patterns, then explore advanced features like security, messaging, and reactive programming. The learning curve is gentle, and the payoff is immediate.
Reference Links
- Official Spring Boot Documentation – https://docs.spring.io/spring-boot/docs/current/reference/html
- The most comprehensive and up-to-date resource, essential for deep dives into any feature.
- Spring Initializr – https://start.spring.io
- The official project generator, perfect for starting new projects with the right dependencies.
- Baeldung Spring Boot Tutorials – https://www.baeldung.com/spring-boot
- High-quality, practical tutorials covering everything from basics to advanced topics, with working code examples.
- Examples – https://www.baeldung.com/spring-boot


