Spring Boot

A Spring application without assembling the infrastructure by hand

Spring Core already knows how to create beans, wire dependencies, and manage the container. But a regular application still needs a lot of repetitive setup: dependencies, configuration, startup, logging, and infrastructure components. Spring Boot takes over a large part of this work and lets you move faster from project setup to the application code itself.

Spring Boot does not replace Spring Core. It is built on top of it and automatically prepares a typical environment based on what is present in the project and which settings the developer provides.

What is inside this section

• Spring Boot Basics. We will see what a minimal Boot application looks like and what happens when it starts.
• Starters. We will see how to add ready-made dependency sets for common tasks.
• Auto-configuration. We will understand where automatic setup comes from and why it does not prevent us from defining our own beans.
• Application Configuration. We will learn to pass settings to the application through files and the external environment.
• Configuration Properties. We will group related settings into typed Java objects.
• Profiles. We will separate configuration for different environments and startup scenarios.
• Logging. We will cover the standard way to write diagnostic messages and control logging levels.
• Actuator. We will meet ready-made technical endpoints for observing a running application.
• Application Startup. We will connect the stages of context startup with code that should run after it is ready.

The topics move from starting the application to external configuration and operating it. After this section, the familiar SpringApplication.run(...) line will stop looking like magic: you will understand which Spring Boot mechanisms stand behind it and where to control them.