How to Build and Deploy Spring Boot Application - The Ultimate Guide

What is Spring Boot All About?

Spring Boot is a framework built on top of Java that makes it much easier and faster to develop applications. Unlike traditional Java applications that required a lot of setup and configuration, which in turn slowed down development, Spring Boot primarily removes the repetitive tasks by offering pre-configured templates and tools. With this, developers can focus more on writing the actual logic of the app.

• Automatic SetupIt can handle most of the configuration for you and reduces manual setup work.
• Built-In ServerCan run your application instantly without the need for installing a separate web server.
• Starter PackagesYou can get the right dependencies quickly with pre-configured starter kits.
• Easy MonitoringCan easily track the application’s health and performance with built-in tools.
• Cloud ReadyThe deployment is quite stress-free with cloud platforms and AI agent development tools.
• Simple IntegrationsCan easily connect with APIs, databases, and AI services with minimal effort.

Spring Boot vs Other Frameworks: Know the Differences

Ever wonder how Spring Boot stacks up? Get a clear idea with the following comparison of Spring Boot and other frameworks.

ℹ️ Bottom Line: Considering the above comparison table, Spring Boot stands out for its strong enterprise adoption, security features, and all the others. This makes it a perfect choice for modern business applications.

Spring Boot Development Environment: What You Need to Start

It is vital to set up a development environment before building an application with Spring Boot for smooth and efficient coding. Here is what you will need before you think of how to build and deploy Spring Boot application.

1. Install Java (JDK25)

Spring Boot 4.x requires Java 17 or later. Java JDK 25 is the current LTS version recommended for new projects.

# Verify Java installation
java -version

# Example output
openjdk version "21.0.7"

2. IDEs (IntelliJ, Eclipse)

You need an Integrated Development Environment (IDE) like IntelliJ IDEA or Eclipse. These tools offer features like intelligent code completion, debugging support, and built-in terminal access to make the development process much easier.

3. JDK and Maven/Gradle

Spring Boot runs on Java, and it is vital to install the latest Java Development Kit (JDK). Besides, you also need to build automation tools like Maven or Gradle to manage dependencies, compile code, and package your application.

# Verify Maven installation
mvn -version

# Example output
Apache Maven 3.9.x

4. Spring Initializr

Spring Initializr, a web-based generator, is vital for starting your project. It helps you create a basic Spring Boot project in a few clicks. You can even choose a build tool like Maven or Gradle, Java version, and the required dependencies. When generated, you can import it into your IDE, and with that, you shall start coding.

Project Structure Overview of a Spring Boot Application

Here’s how a typical Spring Boot application is structured, from the ‘client’ all the way down to the ‘database.’

1. Presentation Layer 2. Service Layer 3. Repository Layer 4. Database & Infrastructure View All Layers

Client

Browser • Mobile • API

HTTP / HTTPS

PRESENTATION LAYER

@RestController

HTTP request routing

Response serialization

Returns JSON responses

Request Mapping

@GetMapping • @PostMapping

@PutMapping • @DeleteMapping

DTO / Validation

@RequestBody • @Valid

@ResponseBody • @Validated

Next: Service Layer ↓

Security Filter Chain

JWT • OAuth2 • Basic Auth • @PreAuthorize • Role-based access

SERVICE LAYER

@Service

Business logic

Orchestration

@Transactional

Transaction boundaries

Rollback rules

Event / Async

@EventListener • @Async

@Scheduled

↑ Presentation Layer Next: Repository Layer ↓

REPOSITORY / DATA ACCESS LAYER

JpaRepository

CRUD + paging

Derived queries

Custom @Query

JPQL • Native SQL

Projections

Cache Layer

@Cacheable • @CacheEvict

Redis • Ehcache

↑ Service Layer Next: Database & Infrastructure ↓

DATABASE / INFRASTRUCTURE

RDBMS

PostgreSQL • MySQL

NoSQL

MongoDB • Redis

Message Queue

Kafka • RabbitMQ

CROSS-CUTTING CONCERNS

Actuator

Logging / Tracing

Exception Handler

AOP

↑ Repository Layer Restart Stepper ↻

How to Build a Spring Boot Application [Step-by-Step Guide]

If you are wondering how to build a Spring Boot application, then this section will give you a clear view of a structured approach. Whether you are starting a new project or looking to create a web application using Spring Boot, here is the process to follow:

1. The Entry Point

Generate a new project using Spring Initializr. Then, choose the project type, Java version, and dependencies. With this, you shall download and import the project into your IDE.

Every Spring Boot app starts with a main class annotated with @SpringBootApplication

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

2. Controller - Handles the HTTP Requests

The controller layer receives the incoming requests and returns responses.

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

    @Autowired
    private UserService userService;

    @GetMapping
    public List<User> getAllUsers() {
        return userService.findAll();
    }

    @PostMapping
    public User createUser(@RequestBody User user) {
        return userService.save(user);
    }

    @GetMapping("/{id}")
    public ResponseEntity<User> getUserById(@PathVariable Long id) {
        return userService.findById(id)
            .map(ResponseEntity::ok)
            .orElse(ResponseEntity.notFound().build());
    }
}

3. Service - Business Logic Lives Here

The service layer handles the business operations and coordinates data flow between controllers and repositories.

@Service
public class UserService {

    @Autowired
    private UserRepository userRepository;

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

    public Optional<User> findById(Long id) {
        return userRepository.findById(id);
    }

    public User save(User user) {
        return userRepository.save(user);
    }
}

4. Repository - Database Interactions

Spring Data JPA handles all the SQL for you. What you have to do is just define the interface.

@Repository
public interface UserRepository
    extends JpaRepository<User, Long> {

    // Spring generates SQL for all basic CRUD automatically.
    // Add custom queries when needed:
    List<User> findByEmail(String email);
}

5. Configure Your Application Settings

You can either use application.properties or application.yml to set up configurations such as database connections, port number, logging level, etc.

# Server
server.port=8080

# PostgreSQL
spring.datasource.url=jdbc:postgresql://localhost:5432/mydb
spring.datasource.username=postgres
spring.datasource.password=yourpassword

# JPA / Hibernate
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

# Logging
logging.level.org.springframework=INFO

6. Run and Test Locally

Use your IDE or command line (mvn spring-boot:run or gradle bootRun) to launch the application. Launch the browser or Postman to test the endpoints and ensure everything works as expected.

# Maven
mvn spring-boot:run

# Gradle
gradle bootRun

# Test your endpoint
curl http://localhost:8080/api/users

Testing the Spring Boot Application

Thorough testing is essential before any application reaches production. Spring Boot itself provides built-in testing tools that help verify the business logic and ensure all the application layers work together as expected.

Unit Tests

A unit test is for inspecting a single class or method in complete isolation, with dependencies replaced by mocks. They actually run in milliseconds.

@ExtendWith(MockitoExtension.class)
class UserServiceTest {

    @Mock
    private UserRepository userRepository;

    @InjectMocks
    private UserService userService;

    @Test
    void shouldReturnUserById() {
        User mockUser = new User(1L, "Yadavi");
        Mockito.when(userRepository.findById(1L))
               .thenReturn(Optional.of(mockUser));

        Optional<User> result = userService.findById(1L);
        assertThat(result).isPresent();
        assertThat(result.get().getName()).isEqualTo("Yadavi");
    }
}

Integration Tests

Integration tests load the application context and validate how multiple layers interact. They are commonly used to test the repositories, services, and database operations.

@SpringBootTest
@Testcontainers
class UserRepositoryIntegrationTest {

    @Container
    static PostgreSQLContainer<?> postgres =
        new PostgreSQLContainer("postgres:16");

    @DynamicPropertySource
    static void props(DynamicPropertyRegistry registry) {
        registry.add("spring.datasource.url", postgres::getJdbcUrl);
    }

    @Autowired
    UserRepository userRepository;

    @Test
    void shouldSaveAndFindUser() {
        User saved = userRepository.save(new User("Bob"));
        assertThat(userRepository.findById(saved.getId())).isPresent();
    }
}

API / Slice Tests

API or slice tests focus on the web layer. By loading only the controllers and related components, they provide quick feedback while making sure the endpoints return the expected responses.

@WebMvcTest(UserController.class)
class UserControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @MockBean
    private UserService userService;

    @Test
    void shouldReturnAllUsers() throws Exception {
        Mockito.when(userService.findAll())
               .thenReturn(List.of(new User("Carol")));

        mockMvc.perform(get("/api/users"))
               .andExpect(status().isOk())
               .andExpect(jsonPath("$[0].name").value("Carol"));
    }
}

Securing Your Spring Boot Application

Authentication is a vital part of any production-ready application. Spring Security makes it easy to protect your APIs and implement auth mechanisms such as JWT (JSON Web Tokens).

Add the Dependency

Start by adding Spring Security and JWT dependencies to your project. These libraries provide the foundation for authentication, authorization, token generation, and validation.

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt-api</artifactId>
    <version>0.12.3</version>
</dependency>

Configure Security Rules

After this, create a security configuration class to define how exactly the requests should be handled. In this example, authentication endpoints remain publicly accessible, while every other API route requires a valid JWT token.

@Configuration
@EnableWebSecurity
public class SecurityConfig {

    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) 
        throws Exception {

        http
            .csrf(csrf -> csrf.disable())
            .authorizeHttpRequests(auth -> auth
                .requestMatchers("/api/auth/**").permitAll()
                .anyRequest().authenticated()
            )
            .sessionManagement(session -> session
                .sessionCreationPolicy(SessionCreationPolicy.STATELESS)
            );

        return http.build();
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
}

💡 Quick Tip!
Use @PreAuthorize(“hasRole( ‘ADMIN’ )”) on specific methods to restrict access by role without additional coding.

How to Deploy Spring Boot Application

Once the application is ready to go, there are four main ways you can deploy it. Pick the one based on your team size, traffic expectations, and how often you release.

Starting with packaging your app:

# Maven — creates a fat JAR in /target
mvn clean package -DskipTests

# Gradle
gradle bootJar

# Run the JAR directly
java -jar target/myapp-0.0.1-SNAPSHOT.jar

1. VPS or Cloud VM

This is the traditional approach to deploying applications and works best for small to medium-sized projects. For this, you should install your Spring Boot app on a VPS or a cloud virtual machine like AWS EC2, Azure VM, or DigitalOcean.

Pros:

• + Simple to set up
• + Full OS-level control over your server
• + Cost-effective for single instances

Cons:

• - Manual scaling and updates
• - Less flexible for complex architectures

2. Docker

Dockerize Spring Boot Application uses containers to ensure consistency across development, testing, and production. Docker allows you to package your Spring Boot application with all its dependencies into a single container, which runs consistently across different environments. This is great for teams who want consistent builds and smooth deployments.

# Stage 1: Build
FROM eclipse-temurin:21-jdk-alpine AS builder
WORKDIR /app
COPY . .
RUN ./mvnw clean package -DskipTests

# Stage 2: Runtime (smaller image)
FROM eclipse-temurin:21-jre-alpine
WORKDIR /app
COPY --from=builder /app/target/*.jar app.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "app.jar"]

docker build -t myapp:latest .
docker run -p 8080:8080 myapp:latest

Pros:

• + Write once, run anywhere
• + Easy rollbacks
• + Simplified dependency management

Cons:

• - Requires basic Docker knowledge
• - Container orchestration is needed for scaling

3. Kubernetes

Kubernetes helps manage and scale applications built with a microservice architecture. It can handle container orchestration, scaling, self-healing, and rolling updates. This works for complex, distributed systems or AI development apps with high availability.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: spring-boot-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: spring-boot-app
  template:
    metadata:
      labels:
        app: spring-boot-app
    spec:
      containers:
        - name: spring-boot-app
          image: yourrepo/myapp:latest
          ports:
            - containerPort: 8080
          env:
            - name: SPRING_PROFILES_ACTIVE
              value: "prod"
---
apiVersion: v1
kind: Service
metadata:
  name: spring-boot-service
spec:
  type: LoadBalancer
  selector:
    app: spring-boot-app
  ports:
    - port: 80
      targetPort: 8080

Pros:

• + Highly scalable and resilient
• + Automates much of the infrastructure management
• + Zero downtime deploys

Cons:

• - Steep learning curve
• - Overkill for small applications

4. CI/CD Pipelines

Continuous Integration and Continuous Deployment (CI/CD) pipelines automate the process of testing, building, and deploying Spring Boot apps. Suitable for projects with frequent updates and agile workflows.

name: Build and Deploy

on:
  push:
    branches: [ main ]

jobs:
  build-and-deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Set up Java 21
        uses: actions/setup-java@v4
        with:
          java-version: '21'
          distribution: 'temurin'

      - name: Build with Maven
        run: mvn clean package -DskipTests

      - name: Build & Push Docker Image
        run: |
          docker build -t ${{ secrets.DOCKER_USER }}/myapp:latest .
          echo ${{ secrets.DOCKER_PASS }} | docker login -u ${{ secrets.DOCKER_USER }} --password-stdin
          docker push ${{ secrets.DOCKER_USER }}/myapp:latest

      - name: Deploy to Server via SSH
        uses: appleboy/ssh-action@v1
        with:
          host: ${{ secrets.SERVER_HOST }}
          username: ${{ secrets.SERVER_USER }}
          key: ${{ secrets.SSH_KEY }}
          script: |
            docker pull ${{ secrets.DOCKER_USER }}/myapp:latest
            docker stop myapp || true
            docker run -d --name myapp -p 80:8080 ${{ secrets.DOCKER_USER }}/myapp:latest

Pros:

• + Faster and more reliable deployment.
• + Reduces human error.
• + Supports test automation.

Cons:

• - Initial setup can be time-consuming.
• - Needs ongoing maintenance.

Deploying Spring Boot as a WAR File

At present, the executable JAR files are the preferred option. However, most enterprises still rely on application servers like Tomcat.

Spring Boot allows you to package your application as a WAR file and deploy it to an external server with minimal configuration.

Update the Packaging Type:

<packaging>war</packaging>

Build the WAR File:

mvn clean package

Now, the generated WAR file will be available in the target directory and can be deployed directly to an Apache Tomcat server.

Production Deployment Checklist

Monitoring Spring Boot Applications

Deploying the application only does half of the job. Once things get live, continuous monitoring becomes essential to ensure the performance, availability, and reliability.

By monitoring at regular intervals, teams can identify potential bottlenecks, detect failures early, and maintain a smooth user experience as the traffic expands.

Spring Boot Actuator

Spring Boot Actuator provides the production-ready monitoring capabilities out of the box. It does expose useful endpoints, allowing developers and DevOps teams to track the app’s health and metrics.

Add the dependency:

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

Useful Endpoints

• /actuator/health
• /actuator/metrics
• /actuator/info

These endpoints provide valuable insights into the application status, memory usage, CPU consumption, request counts, and other operational metrics.

Additional Monitoring Tools

For advanced observability, Spring Boot applications are often integrated with:

• Prometheus: Collects and stores application metrics.
• Grafana: Creates dashboards and visualizes performance data.
• ELK Stack: (Elasticsearch, Logstash, Kibana) centralizes and analyzes app logs.
• New Relic: Provides real-time application performance monitoring and alerting.

Together, these tools help monitor performance, detect issues early, and maintain application stability.

Integrating Spring Boot with AI & Chatbots

Spring Boot is the go-to backend framework for building AI-powered applications. Its modular design, REST support, and secure ecosystem make it easy to plug in any AI-related services.

Connecting to OpenAI API

A common use case is sending user prompts to an AI model and returning generated responses. The example below shows how Spring Boot can communicate with the OpenAI API using a simple service class.

@Service
public class OpenAiService {

    private final RestTemplate restTemplate = new RestTemplate();

    @Value("${openai.api.key}")
    private String apiKey;

    public String chat(String userMessage) {
        String url = "https://api.openai.com/v1/chat/completions";

        HttpHeaders headers = new HttpHeaders();
        headers.setBearerAuth(apiKey);
        headers.setContentType(MediaType.APPLICATION_JSON);

        String body = """
            {
              "model": "gpt-4o",
              "messages": [{"role": "user", "content": "%s"}]
            }
        """.formatted(userMessage);

        HttpEntity<String> request = new HttpEntity<>(body, headers);
        ResponseEntity<String> response = 
            restTemplate.postForEntity(url, request, String.class);
        return response.getBody();
    }
}

After that, this service sends user messages to the AI model, receives responses, and makes it available to the rest of your applications. From here, you can expose the functionality through REST endpoints, web applications, or messaging platforms

What You Can Build?

💬 AI Chatbots

With AI chatbot development, you can build intelligent experiences for mobile applications, websites, and messaging platforms while Spring Boot manages the request and conversion flows.

🤖 AI Agents

You can create task-driven AI systems that automate workflows, interact with APIs, process data, and perform business operations autonomously.

🔍 RAG Pipelines

Combine large language models with vector databases to deliver responses based on your organization’s documents and proprietary data.

📊 ML Backends

Use Spring Boot as an API layer that links frontend apps with Machine Learning models with Node.js, Python, or any other framework.

Common Spring Boot Deployment Issues & Ways to Fix Them

These are the common errors that every Spring Boot hits at some point. Also, get the respective fix for each one.

Why Choose Sparkout to Build & Deploy Spring Boot Applications

At Sparkout Tech, we go beyond basic application development. We build intelligent, scalable, and production-ready backend systems using Spring Boot. Our solutions are tailored to support AI-powered platforms, enterprise-grade software, and chatbot-based solutions. Here is what sets us apart:

Proven Expertise
We have delivered Spring Boot applications across diverse industries, including fintech, e-commerce, healthcare, and AI startups.

AI-First Approach
By prioritizing AI and automation, we build systems to integrate AI agents, NLP tools, and machine learning APIs to make your platform smarter and adaptive.

Full-Cycle Support
Our team handles everything from backend architecture design to code development and testing to setting up CI/CD pipelines and handling cloud deployment effortlessly.

Fast Turnaround
We follow agile methodology and use pre-built modules to offer rapid development cycles without compromising on code quality, performance, and security.

Trusted by Enterprises
Being a top AI agent development company, we are known for delivering reliable, maintainable, and scalable backend architectures that power high-demand applications.