Spring Core and Spring Boot are key components of the Spring Framework.
While Spring Core provides the foundational tools for Java application development, Spring Boot simplifies the process by offering pre-configured setups.
Understanding their differences helps developers choose the right tool for building efficient, scalable, and modern applications.
Spring Core Overview
The Spring Core module is the foundation of the Spring Framework, offering essential concepts like:
IOC Container (Inversion of Control)
Dependency Injection (DI)
Autowiring
Using these concepts, developers can create classes with loose coupling, ensuring flexibility and better application management. Loose coupling is a design principle in software development where different components or classes in an application are minimally dependent on each other. This means changes in one class or component have little to no impact on others.
Here’s an example of loose coupling explained in simple terms:
Imagine you have a Notification class that sends messages. Without loose coupling, this class might directly create an EmailService object to send emails. If you later want to send SMS instead of emails, you'll have to modify the Notification class, making it tightly connected to EmailService.
With loose coupling, you can use an interface, like MessagingService, that both EmailService and SMSService implement. Now, the Notification class doesn’t depend on a specific service but on the interface. You can easily switch between EmailService and SMSService without changing the Notification class. This makes the code flexible, easy to maintain, and adaptable to future changes.
In this example, the Notification class is tightly coupled to EmailService. If you want to replace EmailService with, say, SMSService, you will have to modify the Notification class.
To enable the IOC container to manage your classes, you must follow certain (Strategy Design Pattern) design principles during development.
Strategy Design Pattern
Prefer Composition over Inheritance
Use object composition to achieve flexibility by combining behaviors rather than relying on inheritance.Program to Interfaces, Not Implementations
Write code that depends on interfaces instead of specific implementation classes to allow easy swapping of behavior.Open for Extension, Closed for Modification
Design your code so it can be extended with new features without altering the existing code, ensuring stability and scalability.
Dependency Injection
The process of injecting a dependent object into another object is called dependency injection.
Examples of Dependencies
A Car depends on an Engine to run.
A Controller depends on a Service to handle business logic.
Types of Dependency Injection
Constructor Injection
Setter Injection
Field Injection
Constructor Injection
The dependencies are provided through the class constructor.
Setter Injection
The dependencies are injected using setter methods.
Field Injection
The dependencies are directly injected into the fields using annotations like @Autowired in Spring.
Benefits of Dependency Injection:
Improves code flexibility and reusability.
Reduces tight coupling between classes.
Makes unit testing easier by allowing mock dependencies.
IOC Container (Inversion Of Control)
The IOC container is a principle that manages and coordinates dependencies between objects in an application. It handles Dependency Injection by creating both the dependent object and the target object and then injecting the dependent object into the target object automatically.
Spring Beans is the Java classes that IOC manages
Autowiring
Autowiring is a feature in Spring that allows the automatic injection of dependencies into a class. Instead of manually specifying how dependencies should be injected, Spring automatically wires them based on the data type or name of the property.
We can perform dependency injection in 2 ways
1) Manual Wiring
2) Auto wiring
Manual wiring
Manual wiring means the programmer will inform IOC which is dependent obj using the ref attribute like the below
Auto wiring
Auto wiring means the IOC will identify the dependent object and perform DI. In the spring XML approach, auto wiring is disabled by default.
Autowiring has 4 modes
1) byName
2) byType
3) constructor
4) no (default)
Advantages with spring-core
Flexible and Modular
Loose Coupling
Comprehensive Framework
Platform Independent
Support for AOP (Aspect-Oriented Programming)
Flexible and Modular
Spring Core is highly flexible and allows developers to choose and configure only the modules they need for their applications.
Loose Coupling
It promotes loose coupling through Dependency Injection (DI), making the application easier to maintain, test, and scale.
Comprehensive Framework
Spring Core provides a wide range of features for developing web applications, transaction management, security, and more, with strong support for integration with other technologies.
Platform Independent
It allows developers to build platform-independent applications, which can run on any Java platform, making it ideal for building enterprise-level applications.
Support for AOP (Aspect-Oriented Programming)
It supports AOP, allowing cross-cutting concerns like logging, security, and transaction management to be handled separately, making the code cleaner.
Spring Boot Overview
Spring Boot is a framework that simplifies the development of Spring-based applications by minimizing configuration and setup. It provides default configurations, embedded web servers, and a set of tools to speed up development. While it is based on the Spring Framework, it allows developers to create applications quickly and with less effort. You can develop the same types of apps using Spring Boot that you would with the Spring Framework, but with greater efficiency and simplicity.
Differences Between Spring Core and Spring Boot
key differences between Spring Core and Spring Boot in simple language:
Configuration:
Spring Core: Requires a lot of manual configuration (XML or Java-based configuration).
Spring Boot: Provides auto-configuration, meaning it automatically configures the application based on the dependencies, reducing manual setup.
Setup:
Spring Core: You need to set up your server, application context, and dependencies.
Spring Boot: Comes with an embedded server (like Tomcat), so no need for an external setup.
Development Speed:
Spring Core: Takes more time to develop as it requires more configuration and setup.
Spring Boot: Speeds up development with default settings and less boilerplate code.
Application Packaging:
Spring Core: The application needs to be packaged as a WAR file for deployment.
Spring Boot: You can package the application as a self-contained JAR file, making deployment easier.
Learning Curve:
Spring Core: More complex to learn due to manual configuration and setup.
Spring Boot: Easier and quicker to learn because of automatic configurations and less setup.
Advantages of Spring Boot
POM Starters (Simplified Maven Dependencies)
Dependency Version Conflict Solution
Auto Configuration
Embedded Servers
Actuators
POM Starters (Simplified Maven Dependencies)
These are predefined Maven dependencies that simplify adding required libraries to your project. Examples include spring-boot-starter-web for web applications or spring-boot-starter-data-jpa for database access.
Dependency Version Conflict Solution
Spring Boot automatically manages dependency versions to avoid conflicts. It ensures that the right version of libraries is used, reducing the need for manual version management.
Auto Configuration
Spring Boot automatically configures your application based on the libraries you add. For example, adding spring-boot-starter-data-jpa will automatically set up a connection pool and database configuration.
Embedded Servers
Spring Boot includes embedded servers like Tomcat, Jetty, or Netty to run your application. This means you don't need to set up a separate external server for deployment.
Actuators
Actuators provide tools to monitor and manage your application in production. They expose health check endpoints and metrics to ensure your application is running smoothly.
Disadvantages of Spring Boot
Larger Memory Footprint
Limited Flexibility
Larger Memory Footprint
Spring Boot applications often have a larger memory footprint due to embedded servers and additional dependencies.
Limited Flexibility
The auto-configuration feature can restrict customization for developers who need more control over the application setup.
Conclusion
Spring Core is great for building complex applications with full control over configurations, but it requires more setup and can be harder to learn. Spring Boot, built on top of Spring Core, makes development faster and easier by providing automatic configuration and embedded servers, making it perfect for quick projects.
In short, Spring Core gives you more control, while Spring Boot helps you develop applications more quickly with less effort. Use Spring Core for complex, customized apps, and Spring Boot for simpler, faster development.
