Auto-configuration

Spring Boot's mechanism that creates and configures beans for you when a library is on the classpath and you haven't defined your own.

Definition

Spring Boot ships configuration classes guarded by conditions such as "this class is on the classpath", "no bean of this type exists yet" or "this property is set". When the conditions match, Boot creates beans like a JSON mapper, a data source or a web server with sensible defaults. Defining your own bean of the same type makes the auto-configured one step aside, together with the properties it applied.

In practice

Adding spring-boot-starter-web gives you an embedded Tomcat and a configured Jackson mapper without writing any configuration.

Learn it in context

Lessons that use this term.

Spring Boot BasicsBackend

Related terms

Spring beanAn object that Spring creates, configures and hands to other objects, usually one shared instance per application.
Inversion of controlA design where a framework creates your objects and calls your code, instead of your code creating everything and calling the framework.