What is Spring-Boot ? Spring Boot is a Spring Module which Speed up the development . Now what is Spring ? Spring is a dependency injection Framework to make application loosely coupled What is Dependency Injection ? Lets take a example - Java class School is dependent on class Teacher . so we need teacher object in School Class . so injection of teacher object in school class is done by Spring FrameWork Automaticaly So Spring Boot do automatic Configuration which is repetitive in spring as a configuration.