The @Autowired annotation can be used to inject a dependency into a field, a constructor, or a setter method. However, if there are multiple beans of the same type in the application context, Spring will not be able to determine which one to inject by default. To resolve this ambiguity, we can use the @Qualifier annotation to specify the bean id of the desired dependency. Alternatively, we can use the bean id as the name of the field or the parameter of the setter method, and Spring will match it with the corresponding bean.

A bean definition profile is a named logical grouping of bean definitions that can be activated or deactivated in different environments. For example, we can define different profiles for development, testing, and production environments. Spring provides the @Profile annotation to mark a bean definition or a configuration class as belonging to a specific profile. To activate a profile, we can use the spring.profiles.active property or the ConfigurableEnvironment.setActiveProfiles() method.
The @ActiveProfiles annotation is a class-level annotation that is used in conjunction with the Spring TestContext Framework to declare which profiles should be active when loading an ApplicationContext for an integration test. This annotation can be applied to any class annotated with @ContextConfiguration or a meta-annotation that is composed of @ContextConfiguration.