# Spring and Spring Boot — Spring Boot

Source: https://www.skillbyai.com/en/spring-boot/i-what

> The most widely used Java framework, simplified.

## Framework plus conventions

The **Spring Framework** provides dependency injection, web MVC, data access, transactions and much more for Java (and Kotlin). **Spring Boot** makes it practical: sensible defaults, **starters** that bundle compatible dependencies, **auto-configuration** that wires beans based on what is on the classpath and in configuration, an **embedded web server** so the app runs as a plain `java -jar`, and production features such as health checks and metrics. Spring Boot 4 (built on Spring Framework 7) requires Java 17 or later and splits auto-configuration into smaller, focused modules.

## Opinionated Spring, ready to run

Spring Boot builds on the Spring Framework with starters, auto-configuration and an embedded server.

![Three ideas: what Spring Boot is, starters, auto-configuration.](assets/figures/spring-boot/section-1-map.svg) — Figure 1.1 — Spring Boot, starters and auto-configuration.

## A furnished flat

Spring is a well-built building; Spring Boot hands you a furnished flat: you can move in immediately and replace any furniture you do not like.

## Start at start.spring.io

Spring Initializr generates a correct project with chosen versions and starters, avoiding dependency mismatches.

**Quiz:** What does Spring Boot add on top of the Spring Framework?

- [ ] A database engine
- [ ] A new programming language
- [x] Starters, auto-configuration, an embedded server and production features
- [ ] A replacement for Java

*Answer:* Starters, auto-configuration, an embedded server and production features. Conventions and defaults on top of Spring.