Spring Boot is a recent addition to the Spring Framework. It makes starting a Spring based project crazy easy. Before the days of Spring Boot, you as the developer were responsible for creating a project and managing the dependencies. Now you can use the Spring Initializer to download a ready made project with common dependencies cooking into to Maven or Gradle. Spring Boot and Spring Initializer makes your life as a developer easier.
Here is a simple demo of starting a Spring project using Spring Boot.