Spring Dependency Injection and Inversion of Control Container Concepts
Internal
Overview
At the heart of the Spring Framework are the modules that implement the core container, including a configuration model and a dependency injection mechanism. Support for different application architectures, including messaging, transactions and persistence is built in top of the core container.
Inversion of Control Container
Dependency Injection
Spring Dependency Injection Framework
Configuration Model
This section refers to component configuration. Configuration as in external data that is provided to the application in form of properties or environment variables, and that potentially modifies the behavior of the application, is addressed in the "Application Configuration Concepts" section.
Configuration Metadata
XML-based Configuration
Java-based Configuration (@Configuration). Annotation injection is performed before XML injection, thus the XML configuration overrides the annotations for properties wired through both approaches.
Configuration time. Define what that is.
Configuration class.
Component scanning
Autowiring. @Autowired.
Automatic configuration (Spring Boot autoconfiguration).
Application Context
The application context provides:
- Bean factory functionality, inherited from ListableBeanFactory.
- Ability to load file resources, inherited from ResourceLoader.
- Ability to publish events to registered listeners, inherited from ApplicationEventPublisher.
- Ability to resolve messages, inherited from MessageSource.
- Inheritance from a parent context.
The application context is created during the bootstrapping phase of a Spring application.
Beans
Bean name
Bean alias
Collaborator beans
Describe bean initialization process. Who does it?
Stereotypes.
@Bean What is the fundamental difference between @Bean and the rest (@Component, etc.)?