Let's take a moment and review all the things we have done until now to get this example working:

• We have defined a Spring configuration class SpringContext with the @Configuration annotation with a component scan for the com.mastering.spring package
• We have a couple of files (in the preceding package):
  • BusinessServiceImpl with the @Service annotation
  • DataServiceImpl with the @Repository annotation
• BusinessServiceImpl has the @Autowired annotation on the instance of DataService

When we launch up a Spring context, the following things will happen:

• It will scan the com.mastering.spring package and find the BusinessServiceImpl and DataServiceImpl beans.
• DataServiceImpl does not have any dependency. So, the bean for DataServiceImpl is created.
• BusinessServiceImpl has a dependency on DataService. DataServiceImpl is an implementation of the DataService interface. So, it matches the autowiring criteria. So, a bean for BusinessServiceImpl is created and the bean created for DataServiceImpl is autowired to it through the setter.