What is the difference between @Bean and @Component annotations and when can one replace the other?

In the Spring Framework, the annotations @Component and @Bean are used to define beans (objects managed by Spring), but they are used in different contexts:

• @Component is an annotation placed above a class. Spring automatically scans classes with this annotation (when component scanning is enabled) and creates their instances as beans. It is used for simple and quick component definition.

• @Bean is an annotation placed above a method in a class annotated with @Configuration. The method returns an object that Spring registers as a bean. It allows for more flexible bean creation, such as with parameters, logic, etc.

When can one replace the other:

• If you have a simple class without complex creation logic, it is better to use @Component.
• If creating a bean requires additional logic, parameters, or you want to explicitly control creation, use @Bean.

Example:

@Component
public class MyService {
    // simple component
}

@Configuration
public class AppConfig {
    @Bean
    public MyService myService() {
        return new MyService(); // creation logic can be added
    }
}

Thus, @Component is a declarative way, @Bean is programmable.