Bean vs Component
Component and @Bean do two quite different things, and shouldn't be confused.
@Component (and @Service and @Repository) are used to auto-detect and auto-configure beans using classpath scanning. There's an implicit one-to-one mapping between the annotated class and the bean (i.e. one bean per class). Control of wiring is quite limited with this approach, since it's purely declarative.
@Bean is used to explicitly declare a single bean, rather than letting Spring do it automatically as above. It decouples the declaration of the bean from the class definition, and lets you create and configure beans exactly how you choose.
- @Component auto detects and configures the beans using classpath scanning whereas @Bean explicitly declares a single bean, rather than letting Spring do it automatically.
- @Component does not decouple the declaration of the bean from the class definition where as @Bean decouples the declaration of the bean from the class definition.
- @Component is a class level annotation whereas @Bean is a method level annotation and name of the method serves as the bean name.
- @Component need not to be used with the @Configuration annotation where as @Bean annotation has to be used within the class which is annotated with @Configuration.
- We cannot create a bean of a class using @Component, if the class is outside spring container whereas we can create a bean of a class using @Bean even if the class is present outside the spring container.
- @Component has different specializations like @Controller, @Repository and @Service whereas @Bean has no specializations.