What is Spring Architecture

Developing Java applications can get difficult when handling user requests, databases, business logic, and security. What if you could just simplify the whole process? This is what Spring Framework does. The Spring architecture provides a way for any application to be organized in a structure by separating it into layers, managing dependencies automatically, and managing cross-cutting concerns for you, for example, logging and transactions. In this article, we will learn about Spring Architecture, dive deeper to discover its components, and see how the framework is providing you with a way to build scalable, robust, and maintainable applications, step by step.

What is Spring Framework in Java?

Spring is a framework in Java that helps you create enterprise-level applications by providing a detailed infrastructure and modules to choose from. You can think of Spring as a supermarket where everything is available, and you can choose what you want to add to the cart. This makes Spring a modular framework. 

Spring follows the POJO concept, meaning the “plain old Java objects,” Aspect-oriented programming (AOP), and Dependency injection (DI), all of which make it easier to build enterprise-level applications.

Spring Framework is the basis for all the other famous Java frameworks that you might have heard about, like Spring Boot, Spring Cloud, etc. Hence, learning and understanding the Spring Framework architecture will form the foundation of your software application development. Once you get the hang of the basic Spring architecture, understanding Spring Boot architectures as well as Spring MVC architectures will become easier. 

Key Benefits of Using Spring

Spring in Java has become so popular because of how it has simplified Java development. Not only this, there are so many other key benefits, some of which we have listed below:

• Spring uses the Dependency Injection (DI) feature, which means that the classes don’t have to manually create their dependencies. Spring takes care of that automatically. 
• Inversion of Control (IoC) Container manages application objects (called “beans”) and automatically injects dependencies where needed, promoting loose coupling.
• Spring also supports multiple configuration approaches, and developers can choose the simplest one depending on the project.
• The database connection and transactions are also easily manageable, which is also a plus point of the Spring Framework.
• Also, Spring is easy to set up, and you can start with your project quickly with embedded servers and auto-configuration.

All these reasons contribute towards making Spring a go-to choice for Java developers who are looking for robust, flexible, and maintainable application development.

Understanding Software Architecture Concepts

Before we dive into the Spring architecture, let us first understand what exactly software application architecture is and why we need structured architecture in development.

Application architecture basically defines how different parts of the application are set up. It also decides how each of these modules will interact with the others. It divides the application into layers that depict a clear structure and working of the application. Below, we have visualized a simple structure. This approach helps in maintaining the code for better maintainability and clarity.

A few reasons why this structure is needed in software development are:

• Separation of Concerns: Since each layer has a specific role, it makes code easier to understand and manage.
• Reusability: This way, code in one layer (like services or repositories) can be reused in multiple places.
• Scalability: A structured architecture makes it easier to add new features or modules without breaking existing code.
• Maintainability: When code is well organized and divided into separate layers, bugs and changes are easier to track and fix.
• Testability: This might not be so intuitive, but well-separated layers make unit testing easier and more effective.

What Is Spring Architecture?

Spring Architecture is a well-organized structure that helps developers build robust and scalable Java applications by providing a clear way to manage different components of the application. Just as a supermarket has different sections (fruits, dairy, bakery) to keep things organized and easy to find, Spring Architecture divides an application into multiple layers, each responsible for a specific task.

There are a few concepts that make development easier in the Spring architecture, like Dependency Injection (DI), IoC, and Aspect-Oriented Programming (AOP). These were mentioned in the previous sections, but let us look at them in a bit more detail.

Core Concepts of Spring Architecture

At a high level, Spring Architecture divides an application into several layers, each of which is responsible for a specific task:

• Inversion of Control (IoC): Instead of your code creating objects and managing dependencies (connections), Spring’s IoC Container takes care of object creation and manages the dependencies automatically. This promotes loose coupling, making your application easier to maintain and test.
• Dependency Injection (DI): With DI, Spring injects the required dependencies into a class, so developers don’t have to manually create objects or manage their lifecycles. For example, if your service class needs a repository to access the database, Spring will automatically inject the correct repository object.
• Aspect-Oriented Programming (AOP): Spring allows you to separate cross-cutting concerns like logging, security, or transaction management from your business logic. So instead of cluttering your service classes with logging or transaction code, you can define these concerns separately and apply them automatically where needed.

The typical layered structure of Spring Architecture looks like this:

1. Presentation Layer (Controllers): This layer is responsible for handling user input, processing HTTP requests, and returning responses.
2. Service Layer (Business Logic): This layer contains the main logic of the business used in the application.
3. Repository Layer (Data Access): This is also known as the Data Access layer, and it manages interaction with the database.

Inside the Spring framework, there are modules that you can choose based on your project needs, such as:

• Spring Core
• Spring AOP
• Spring Data
• Spring MVC
• Spring Security

Core Components of Spring Architecture

Now that we have a basic understanding of how Spring Architecture organizes applications into layers and the important concepts like IoC, DI, and AOP, let us take a closer look at the core components of the Spring Framework. Here is a visualization of Spring architecture:

If you look at the image above, the Spring Framework consists of several core functional components, such as Core Container, Data Access/Integration, Web, AOP, Instrumentation, and Testing. Each of these components contains specific modules that provide concrete functionality. For example, the Data Access/Integration component includes modules like JDBC, ORM, JMS, and Transactions.

1. Spring Core Container

The Spring core container is the heart of the Spring architecture. It provides all the basic functionality, like Inversion of Control (IoC) container and the ApplicationContext, which manage objects (beans) and their dependencies. The core container has the following modules: Beans, Core, Context, and Expression Language. 

• Spring Core: As the name suggests, this is the core of the Spring Framework. This means that all the core functionalities like dependency injection (DI) and IoC are present in this module. 
• Spring Beans: This module provides the BeanFactory, which is the main control centre for accessing and managing beans. Throughout the lifetime of a bean, everything is managed by this module. 
• Spring Context: This module is an extension of the Spring Beans Module, providing advanced containers that provide features like internationalization, resource loading, and event publication. Both of these modules combined help build more complex applications.
• Spring Expression Language (SpEL): Spring has its own Expression Language that enables querying and manipulating object properties, calling methods, performing condition checks, and working with variables at runtime. 

2. Data Access / Integration

This component is the bridge between applications and databases or any other data sources in the spring architecture. This modules hold the following modules:

• Spring JDBC: It provides a simplified abstraction layer over standard JDBC, and manages connection codes automatically, like handling exceptions and managing resource cleanup. It makes transaction management and database operations safer and easier. 
• Spring ORM (Object-Relational Mapping): This module enables Spring to integrate with other ORM models, such as Hibernate, JPA, and JDO. It provides an abstraction layer and easily integrates ORM technologies with Spring features like transaction management and caching.
• Spring Data: Spring Data is a unified programming model designed to work with databases, NoSQL, as well as cloud data services. It offers features such as query generation, pagination, sorting, and repository-based data access patterns. 
• Spring Transaction: It helps manage database transactions automatically, so developers don’t have to write extra code to start, commit, or roll back transactions. It also supports different ways to handle transactions, making it easy to work with different databases or data systems safely and consistently.

3. Web

The Web module in the Spring architecture helps developers create web applications and web services with a modular approach. The modules inside the Web are:

• Spring MVC (Model-View-Controller) is designed to manage web applications. Spring MVC provides developers with a comprehensive framework for developing web applications. Spring MVC handles HTTP requests and responses, performs form handling, allows developers to perform data binding, implements data validation, performs view resolution, and provides developers with a range of options for view technology, including JSP, Thymeleaf, and Velocity, among others. The Spring MVC framework in the Spring architecture provides developers with unlimited flexibility in designing the setup of the presentation layer.
• Spring WebFlux: It is designed for reactive programming in applications where high concurrency or scalability, like applications expected to have many clients at any given time. It is built on reactive streams and performs as asynchronous and non-blocking capabilities by using reactive streams with Netty or Servlet 3.1+ containers to build applications. WebFlux also helps developers build reactive web applications with reactive HTTP clients and reactive data access.
• Spring Web Services: This module in the Spring architecture provides developers with a way to create SOAP-based and RESTful web services. It has capabilities to generate WSDL from Java classes and vice versa, so that developers can define web service contracts and automatically create the matching Java classes. Thus, keeping the contract-first approach of web service development very clear.

4. Spring AOP (Aspect-Oriented Programming)

The Spring AOP (Aspect-Oriented Programming) module present inside the Spring architecture helps separate common tasks that are needed across multiple parts of an application, known as cross-cutting concerns, from the main business logic. Instead of having to use the same code repetitively in various application classes, AOP lets developers define these general tasks in one location and use them in a consistent manner anywhere in the application. 

So, what are some examples of cross-cutting concerns? The cross-cutting concerns could be logging in, user permission checks, or database transaction handling. 

Without AOP, developers would have to add the same logging or security checks manually in every application method, service, and controller, which adds replication of code and makes the code far less manageable.

AOP works by defining aspects that modularize cross-cutting concerns, keeping your application code cleaner and easier to maintain. 

5. Instrumentation

This is the final component of the Spring architecture that we haven’t discussed yet. Instrumentation is more of a module than a separate component, like the core container or the web container. It provides support for class instrumentation and classloader modifications; its purpose is to help developers adjust or observe behaviours of application classes, at runtime, without modifying their source code. Essentially, both modules, Aspect and Instrumentation, function in the background and apply cross-cutting behaviours designed to simplify development and make managing application changes easier.

6. Test

The Test module in Spring architecture is not exactly a component, but is an integral part of the architecture regardless. It provides support for unit testing and integration testing of Spring applications, making it easier for developers to test their code in a controlled and consistent way inside the framework itself. Some of the notable features of the Test module are:

• Spring TestContext Framework: This allows developers to load a Spring application context for tests, so that beans and dependency injection work exactly as in the real application.
• JUnit Integration: Spring seamlessly integrates with popular testing frameworks like JUnit and TestNG, allowing tests to run in a Spring-managed context with all beans properly injected.
• Web Testing Support: For the Spring MVC applications, the MockMvc class allows developers to test controllers by simulating HTTP requests and checking responses, without starting the whole web server.

There are several other methods, one for every component and the sub-component. Before the deployment of the application, this module in the architecture is heavily used. Also, being already integrated inside the framework itself, it is easier for developers.

Spring MVC vs Spring Framework vs Spring Boot

Many beginners get confused between Spring MVC, Spring Framework, and Spring Boot when studying the Spring architecture because they sound very similar. But they are actually quite different and do not represent the same things. 

• Spring Framework is a comprehensive framework that provides a wide range of tools and modules to build enterprise-level Java applications. It offers features like Dependency Injection, AOP, transaction management, and modular architecture.
• On the other hand, Spring MVC is a part of the Spring Framework that helps developers build web applications using the Model-View-Controller design pattern. It handles HTTP requests, form handling, and view resolution, and integrates easily with other Spring features.
• Spring Boot is built on top of the Spring Framework and simplifies application development by providing auto-configuration, embedded servers, and starter dependencies. It helps developers quickly set up production-ready applications with minimal configuration.

To sum it up, Spring Framework is the whole application, Spring MVC is a part of that framework, and finally Spring Boot is based on Spring Framework, taking that as a base.

Bean Lifecycle in Spring

Now that we have a pretty solid grasp on the basic aspects of Spring Architecture, let us also understand how Spring handles a bean’s lifecycle behind the scenes. In Spring, a bean is simply an object that is instantiated, configured, and managed by the Spring IoC container.

Understanding the Bean Lifecycle will help you to see how Spring manages the creation, configuration, and destruction of beans in an organized way, so you don’t have to manage the bean lifecycle manually.

Step by Step Lifecycle

Below, we have listed the whole lifecycle of a Bean inside the Spring architecture and framework in five steps.

1. Bean Definition and Instantiation

First, the Spring framework loads the bean definitions from the configuration files (XML) or other classes decorated with the annotations of @Component, @Service, @Repository, or @Controller.

Then, according to the Spring architecture, it creates an instance of the bean using its default constructor or a custom one if one is defined.

2. Dependency Injection (Property Setting)

As previously mentioned, after creating the bean instance, the Spring framework will automatically inject any required dependencies into the bean’s properties.

This injection is based on configuration or annotations like @Autowired, so you are not forced to manually create or assign those dependencies in your code. The Spring architecture is designed in such a way as we have discussed above. 

3. Awareness Interfaces (Optional Setup)

If the bean implements interfaces that are property aware, such as BeanNameAware and BeanFactoryAware, Spring will pass the bean’s name (or the BeanFactory) to the bean instance.

This is for advanced use cases of the Spring architecture when the bean wants to know internally its identity or the container it is managed in.

4. Initialization

Lastly, before the bean is made available for use, Spring performs optional initialization logic.

This can include calling methods that are annotated with @PostConstruct, or whichever method was defined in the init-method.

It can be useful when you want to set up some resources needed in the bean (perhaps opening a file) just after the bean is constructed and set up completely.

5. Destruction (Optional Cleanup)

Spring calls destruction methods, which are annotated with @PreDestroy or specified in destroy-method, when the application shuts down. This allows the bean to clear up any resources, like closing connections to databases or releasing file handles, if it chooses to.

Spring Configuration Approaches

Configuring your application in Spring means telling Spring what beans to create and how to work with those beans. Spring architecture has defined several ways to configure your application, which gives you flexibility based on your needs and project complexity.

Here are the three main configuration approaches in Spring:

1. XML-Based Configuration

This represents the traditional method for configuring Spring applications. Configuring Spring applications using this model requires identifying what beans you want to define, their dependencies, and defining them all within an XML configuration file (typically named applicationContext.xml). You then define each bean using the <bean> tag with its class, properties, and dependencies.

Example:

<bean id="myService" class="com.example.MyService">
    <property name="repository" ref="myRepository"/>
</bean>

• The advantages of XML configuration are that you can have a centralized configuration in one file. This is also easy to maintain and understand for small projects. 
• It is actually hard to maintain in large projects, and this type of configuration usually requires more typing.

2. Annotation-Based Configuration

This method is much more contemporary and popular nowadays in the users of Spring. You use annotations like @Component, @Service, @Repository, and @Controller directly in your Java classes to let Spring know that they are beans, in place of XML. You will inject dependencies using @Autowired.

Example:

@Component
public class MyService {
    @Autowired
    private MyRepository myRepository;
}

This type of configuration is easier to read and implement in the Spring architecture. There is no need for XML configuration files once you implement the annotation-based configuration. Because of this, this method is more recommended.

3. Java-Based Configuration

This approach uses plain Java classes to configure Spring beans using the @Configuration and @Bean annotations. It gives you full power of Java while configuring beans and their dependencies.

Example:

@Configuration
public class AppConfig {
    @Bean
    public MyService myService() {
        return new MyService(myRepository());
    }
    @Bean
    public MyRepository myRepository() {
        return new MyRepository();
    }
}

There are several advantages of the Java-based configurations. This type of configuration is actually Type-safe and easy to refactor, making it very flexible to implement. This method is best for large and complex applications. 

Which Approach Should You Use?

• For beginners, annotation-based configuration is the easiest and most recommended way to start.
• If you need full control or are working in legacy projects, XML configuration may still be useful.
• For advanced setups or when you prefer code over configuration files, Java-based configuration is a great choice.

Real-World Example: How Spring Architecture Works in a Web App

To better understand the Spring Architecture while building a real web application, let’s look at a simple, step-by-step flow of how an HTTP request is handled in a typical Spring-based web application.

Step-by-Step Flow of a Web Request

Step 1: HTTP Request

A user opens their browser and sends an HTTP request by entering a URL or submitting a form on a website.

Step 2: Controller Layer

The request first reaches the Controller layer (part of Spring MVC). The controller is responsible for handling the HTTP request, processing input parameters, and forwarding the request to the business logic layer.

Example: 

@GetMapping("/products")
public List<Product> getProducts() {
    return productService.getAllProducts();
}

Step 3: Service Layer

The Controller calls a method from the Service Layer, where the main business logic is written. The Service layer processes the request, performs validations, applies business rules, and calls the data access layer when needed.

Example:

public List<Product> getAllProducts() {
    return productRepository.findAll();
}

Step 4: Repository Layer (Data Access Layer)

The Service Layer calls the Repository Layer to interact with the database. Here, Spring Data or Spring JDBC is used to query the database and fetch or store data.

Example:

public List<Product> findAll() {
    return jdbcTemplate.query("SELECT * FROM products", new ProductRowMapper());
}

Step 5: Database

The Repository Layer executes the SQL queries and retrieves data from the database (or inserts/updates data).

Step 6: Response Flow Back

Once the data is fetched, it travels back in reverse order. It goes from Repository to Service to Controller and finally to HTTP Response. After this, the Controller sends the response back to the browser, which displays the result to the user.

• HTTP Request: Sent by the user’s browser (e.g., form submission or URL hit).
• Controller: Receives the HTTP request and delegates it to the Service.
• Service: Contains business logic and coordinates data retrieval.
• Repository: Manages database operations (CRUD).
• Database: Stores and returns data as needed.

Best Practices for Beginners

If you are just starting with Spring and getting familiar with the Spring architecture, adhering to some best practices will allow for cleaner and more maintainable code. Below are five best practices that any beginner should follow:

• Keep configuration simple: Always prefer annotation-based configuration over XML whenever possible. This will make the code more readable and maintainable, and reduce complexity.
• Utilize layer architecture: You should separate your code into Controller, Service, and Repository layers. This will provide structure as your application grows.
• Use Dependency Injection (DI) correctly: Let Spring take care of creating objects and performing dependency injection with @Autowired or constructor injection. You shouldn’t create objects with new inside your classes.
• Define clear bean scopes: Use Singleton scope for beans (most of the time) unless you require a prototype or request scope in order to keep from creating new objects unnecessarily and improve performance.
• Handle exceptions properly: Try to use Spring @ControllerAdvice and @ExceptionHandler for application-wide exception handling. You will keep your error-handling code separate and consistent throughout the application.

Common Beginner Mistakes to Avoid

When beginning to use Spring, there are a number of common pitfalls that new developers will fall into that could create applications that are more difficult to maintain, or even cause the application to break. The following are five things to avoid from the very start:

• Do Not Manually Instantiate Beans: As a beginner, it may be tempting to try to directly create beans with new MyService(). Only let Spring create and manage your beans with the required annotations (@Component) or configuration classes.
• Avoid Tight Coupling: Do not tightly couple your classes by calling dependencies directly from the constructor or methods. Utilize Dependency Injection so that your code is flexible and easier to test.
• Not Using @ComponentScan: Occasionally, a new developer will forget to add @ComponentScan to the configuration classes and assume Spring will detect their beans automatically. Just ensure the package structure is being scanned properly.
• Misunderstanding Bean Scope: Declaring a bean as a prototype instead of declaring it as a singleton, and it still works, is a waste of resources – you just created objects unnecessarily. Understand when to use and why you should use different scopes, ie, singleton, prototype, request, or session.
• Overcomplicating Configuration: A new developer usually will try to achieve too much by trying to configure too many beans in either XML or Java config for no good reason. Use the simple annotated approach unless you absolutely need the advanced configuration.

Conclusion

Spring Architecture provides a flexible and well-organized way to build robust enterprise-level Java applications. By separating an application into clear layers, Presentation, Service, and Repository, and leveraging key concepts like Dependency Injection (DI), Inversion of Control (IoC), and Aspect-Oriented Programming (AOP), Spring helps developers write clean and scalable code that is also easy to maintain. Whether it’s managing beans automatically, simplifying database interactions, or handling cross-cutting concerns, Spring takes care of the heavy lifting, allowing developers to focus on business logic.

Understanding Spring architecture and best practices will help you build efficient applications from the start. It will also prepare you for advanced Spring frameworks like Spring Boot, helping you master Spring development in no time. 

Useful Resources:

• 25+ Spring Interview Questions And Answers [2025]
• Spring Boot Interview Questions and Answers
• How to Become a Software Architect in 2025?
• Android Architecture: Layers and its Components
• What is Client-Server Architecture? Explained

Spring Architecture – FAQs