Convention over configuration and fat JAR files
Spring Boot targets the fast development of production-ready Spring applications by being strongly opinionated about how to set up both core modules from the Spring Framework and third-party products, such as libraries that are used for logging or connecting to a database. Spring Boot does that by applying a number of conventions by default, minimizing the need for configuration. Whenever required, each convention can be overridden by writing some configuration, case by case. This design pattern is known as convention over configuration and minimizes the need for initial configuration.
Configuration, when required, is, in my opinion, written best using Java and annotations. The good old XML-based configuration files can still be used, although they are significantly smaller than before Spring Boot was introduced.
Added to the usage of convention over configuration, Spring Boot also favors a runtime model based on a standalone JAR file...
