You want to build a Java web application or REST API. You’ve heard everyone uses Spring Boot. But what is it exactly, and why does it exist? This article answers that — clearly — before writing a single line of code. What Is Spring Boot? Spring Boot is an opinionated framework for building Spring-based Java applications with minimal configuration. Break that down: Spring-based — it sits on top of the Spring Framework, which has been the dominant Java application framework since 2003 Minimal configuration — you describe what you want (a web app, a database connection), and Spring Boot figures out how to set it up Opinionated — it makes sensible default choices so you don’t have to make every decision yourself The one-line version: Spring Boot lets you go from a blank project to a running application in minutes, with production-ready defaults built in.

A Spring Boot project looks simple on the surface but has a specific structure with specific conventions. Understanding it upfront saves hours of confusion later. The Standard Layout order-service/ ├── pom.xml ├── mvnw # Maven Wrapper script (Unix) ├── mvnw.cmd # Maven Wrapper script (Windows) ├── .mvn/ │ └── wrapper/ │ └── maven-wrapper.properties └── src/ ├── main/ │ ├── java/ │ │ └── com/devopsmonk/orderservice/ │ │ └── OrderServiceApplication.java │ └── resources/ │ ├── application.

In this article you’ll create a Spring Boot application, add a REST endpoint, and run it — all in under 10 minutes. Then you’ll understand exactly what each piece does. What you’ll build: A Spring Boot app that responds to GET /hello with "Hello, Spring Boot!". Prerequisites JDK 21 or higher installed (java -version to verify) Maven 3.9+ installed (mvn -version to verify) An IDE — IntelliJ IDEA (recommended), VS Code with Java extension, or Eclipse Step 1: Generate the Project Go to start.