Spring explained: What is Spring? And what is Spring Boot?

Java is one of the most widely used programming languages. It’s used for developing things like mobile applications, but also large-scale enterprise systems. Because of Java’s popularity, different frameworks and tools have appeared to simplify the development process. Spring has become one of the most popular Java frameworks. In this article, we will look at the Spring framework and the related Spring Boot microframework.

Spring = Spring Framework

The word Spring refers to the Spring Framework. Spring is an open-source, lightweight Java framework that provides infrastructure support for developers creating cloud native applications. The framework contains a large body of predefined code which developers can use and to which they can add their own code. Spring removes a lot of tedious configuration work, so developers can focus on actually writing the application.

Developers do not only use the Spring Framework because of the coding efficiency, though. Java programs can be quite complex, and they often feature many heavyweight components. These components depend on the underlying operating system (OS) for their appearance and properties. Spring however is more lightweight, because the framework is quite good at using system resources efficiently.

Since Spring leverages interfaces and open standards, it’s also very extensible. The release of Spring Boot in 2014 was a huge next step in extending the Spring Framework with a set of structures and tools for creating microservice architectures. We’ll dive deeper into Spring Boot later on in this article.

The Spring Framework enables a POJO-based programming model. POJO stands for “Plain Old Java Object” and is not bound by any special restriction other than those forced by the Java Language Specification, and does not require any classpath. This model will make your code easier to read, allowing you to be more productive.

Spring is also well-known for the implementation of the Inversion of Control principle, also known as dependency injection (DI). With dependency injection, the Spring container injects objects into other objects or dependencies. This process is fundamentally the inverse (that’s why it’s called Inversion of Control) of the bean itself controlling the instantiation or location of its dependencies by using direct construction of classes, or a mechanism such as the Service Locator pattern.

Spring ≠ Spring Boot

Many people use the terms Spring and Spring Boot interchangeably, but they’re not the same! As we stated earlier, the word Spring refers to the Spring Framework. Spring Boot is actually more of an extension of the Spring framework. While the Spring framework focuses on providing developers flexibility, Spring Boot aims to shorten the code length and allows you to build a stand-alone application with minimal or zero configurations. More on that below!

Spring Boot = microframework built on top of the Spring framework

Spring Boot is a tool that makes developing web applications and microservices with the Spring Framework a lot easier for Java developers. As handy the Spring Framework might be, you will still need a lot of time and knowledge to configure and deploy your Spring applications. Spring Boot makes things a lot easier for you, and it does so through three core capabilities.


Spring Boot comes with built-in autoconfiguration capabilities, which means it automatically configures both the Spring Framework and your third-party packages based on your settings. This feature enables you to start developing your Spring-based applications fast, and reduces human error.

Opinionated approach

Spring Boot uses an opinionated approach to add and configure starter dependencies based on the needs of your project. Instead of the developer making all the decisions and setting up everything manually, Spring Boot will choose which packages to install and which default values to use. You can define the needs of your project during the initialization process with Spring Boot Initializr. The best part about Spring Boot Initializr is that it only requires you to fill out a web form, there’s no coding needed.

Standalone applications

Spring Boot helps developers create standalone applications. These applications can run on their own, without relying on an external web server. Spring Boot embeds a web server like Tomcat or Netty into your application during the initialization process. As a result, you can launch your application on any platform immediately: just hit the run command! Naturally, you can opt out of this feature should you want to do so.

Want to get started with Spring and Spring Boot?

Register for one of our Spring Core training courses! The course covers the major features of both Spring and Spring Boot. You will learn about configuration, data access, REST, AOP, auto-configuration, actuator, security, and the Spring testing framework to build enterprise and microservices applications. After this course, you will be ready to start creating enterprise and cloud-ready applications!

The Campus, Charlotte Van Rompaey 9 February, 2022
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