Difference between Spring and Spring Boot

Both Spring and Spring Boot are products of the larger Spring ecosystem, but they serve distinct purposes and offer different features. Let's dive into the key differences between them:

1. Purpose:

Spring Framework: Spring's core features can be used by any Java application. It provides comprehensive infrastructure support for configuring and building enterprise-grade applications, focusing on "plumbing" and foundational building blocks.
Spring Boot: Spring Boot is built on top of the Spring framework and simplifies the process of building production-ready applications with minimal setup. It provides a convention-over-configuration paradigm to reduce developer effort in building standalone and web-based Spring applications.

2. Configuration:

Spring Framework: Historically, Spring applications required extensive XML configuration. Though annotation-based configuration is now more common, setup and configuration are more manual compared to Spring Boot.
Spring Boot: Spring Boot favors Java-based configuration and annotations. It introduces a set of default configurations, settings, and libraries so that you can get started without much boilerplate code and configuration.

3. Project Setup:

Spring Framework: Setting up a new Spring project often required bootstrapping with Maven or Gradle, defining project structure, and adding dependencies manually.
Spring Boot: With tools like the Spring Initializr, setting up a new Spring Boot project is straightforward. It offers a web-based UI to bootstrap a new project with desired dependencies, or you can use Spring Boot CLI for the same.

4. Embedded Server:

Spring Framework: You need to deploy your Spring applications to an external server, like Tomcat or Jetty, manually.
Spring Boot: Comes with embedded servers like Tomcat, Jetty, and Undertow, allowing you to run your application without needing an external server.

5. Opinionated Defaults:

Spring Framework: Provides flexibility with a wide array of options, but that often means you must configure components manually.
Spring Boot: Provides opinionated defaults for quick setup and convention-over-configuration. These defaults can be overridden if needed.

6. Externalized Configuration:

Spring Boot: Makes it easy to externalize configuration, so you can have the same application code run in different environments. It provides features to read from properties files, YAML files, environment variables, and command-line arguments.

7. Spring Boot Actuator:

Spring Boot introduces the Actuator module, providing production-ready features out of the box like monitoring, metrics, and application insights without additional coding.

8. Microservices:

Spring Boot: In combination with Spring Cloud, Spring Boot becomes an excellent choice for building microservice-based architectures. Spring Cloud builds on Spring Boot to enable building cloud-native applications.

9. Popularity and Learning Curve:

Spring Framework: Has a steeper learning curve due to its wide array of configurations and features.
Spring Boot: Easier for beginners to pick up and start developing applications. It simplifies many of the challenges and configurations required by traditional Spring, making it more popular for new projects.

Conclusion:

While Spring Boot and the Spring framework are closely related, the main distinction lies in their primary goals. Spring Boot doesn't replace Spring; instead, it enhances and simplifies the experience of using Spring. If you're starting a new project and want to leverage the power of Spring with minimal hassle, Spring Boot is likely the way to go.