Spring Boot Introduction

Spring Boot is a Java-based framework that helps you build web applications and APIs quickly. You write less setup code, and Spring Boot takes care of most of the configuration work for you.

What Problem Does Spring Boot Solve?

Before Spring Boot, building a Java web app meant writing dozens of configuration files. You had to manually set up servers, connect databases, and wire every component together. Spring Boot removes that burden by providing smart defaults.

Think of it like a pre-furnished apartment. You move in and everything works — you can rearrange things later, but you do not start from scratch.

Spring vs Spring Boot: The Key Difference

Spring is the original framework. Spring Boot is built on top of it with automatic configuration already applied.

Traditional Spring            Spring Boot
─────────────────────         ──────────────────────
Write XML config files   →    No XML needed
Set up server manually   →    Embedded server included
Add many dependencies    →    Starter packs bundle them

What Can You Build with Spring Boot?

• REST APIs for mobile and web apps
• Microservices (small, independent services)
• Backend systems for websites
• Scheduled background jobs
• Real-time data processing apps

How Spring Boot Works — A Simple Diagram

  Your Code
     │
     ▼
┌─────────────────────────┐
│      Spring Boot        │
│  ┌───────────────────┐  │
│  │  Auto Config      │  │
│  │  Embedded Server  │  │
│  │  Starter Packs    │  │
│  └───────────────────┘  │
└─────────────────────────┘
     │
     ▼
  Running App  ◄── Browser / Mobile / API Client

Spring Boot sits between your code and the outside world. It handles the infrastructure so you focus only on your application logic.

Key Features at a Glance

Embedded Server

Spring Boot includes a built-in web server (Tomcat by default). You do not install a separate server — the app runs on its own.

Auto Configuration

Spring Boot detects what libraries you added and configures them automatically. Add a database library, and Spring Boot connects to the database with sensible defaults.

Starter Dependencies

Instead of picking 10 individual libraries, you pick one "starter." For example, spring-boot-starter-web gives you everything needed to build a web app in one line.

Production Ready Features

Spring Boot includes health checks, metrics, and app monitoring through a module called Actuator — covered in a later topic.

Who Uses Spring Boot?

Major companies including Netflix, Amazon, LinkedIn, and Zalando use Spring Boot to power their backend services. It is one of the most widely used Java frameworks in the industry today.

Language Requirements

Spring Boot works with Java, Kotlin, and Groovy. This course uses Java. You need a basic understanding of Java — classes, objects, and methods — to follow along.

Summary

• Spring Boot is a framework that simplifies Java web development
• It removes manual configuration through smart defaults
• It includes an embedded server — no separate installation needed
• Starter dependencies bundle related libraries together
• It is widely used in professional and enterprise software