Why Spring Boot?
Before Spring Boot, building a production-ready Spring application required an immense amount of manual boilerplate configuration. You had to configure an explicit pom.xml with correct matching dependency versions, setup a DispatcherServlet, configure a ViewResolver, establish a JDBC Connection Pool, and manually install a Tomcat server.
Auto Configuration
Auto-configuration is the absolute core feature behind Spring Boot.
Building a Boot Web App
Creating a web application structurally using Spring Boot requires almost zero manual configuration aside from establishing the project dependencies.
Spring Boot DevTools
In standard Java enterprise development, altering Java source code traditionally requires you to entirely stop the application server, re-compile the entire project, and launch the server again. This completely ruins developer productivity.
Databases: H2 and MySQL
Spring Boot heavily abstracts mapping Database settings through standard auto-configuration boundaries securely.