Field … in … a bean of type ‘service’ that could not be found

I’m trying to use an object which is in an external library, but when I use the @Autowired property, it is not found by the application.

The main application has the following annotations:

@SpringBootApplication
@ComponentScan(basePackages = {"com.XXXX.prj.business.modules"})
@EntityScan("com.XXXX.prj")
@EnableJpaRepositories(basePackages = {"com.XXXX.prj.business.modules.repositories"})

In the com.XXXX.prj.business.modules I have a class that calls the object of the dependency, called MailService, in this way:

@Component
public class MailNotificatorImpl implements Notificator {

    @Autowired
    private MailService mailService;

Here is the problem, this mailService object is not found as a bean type. The MailService is in an external library, called YYYY-commons. The class of the library has the interface and its implementation, and the implementation has this annotation:

@Service("mailService")
public class MailServiceImpl extends GenericService implements MailService, Serializable {

I don’t know what I’m doing bad because in other application I use in the same way and it’s working.

Can you give me some help in this? Thanks a lot!

Answer

In your component scan, you are only scanning the defined package, and any sub-package from there. This meand that the third party lib is not caught in the component scan, hence the bean is not registered.

The options you have is to:

1. use the @ComponentScan annotation on your main application class and add both your own base package, and the package of the third party lib.

@ComponentScan(basePackages = {"my.base.package", "third.party.package"})
public class MySpringBootApplication{}

2. register the bean yourself by adding something like the below to e.g. your main application class:

@Bean
public MailService mailServiceBean() {
  return new MailServiceImple();
}