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Many similar questions like this, but none of the solution has worked for me yet. I have a Repository interface that extends MondoRepository.

public interface Repository extends MongoRepository<Subject, String> {
    Subject findByName(String name);
And this is the subject class
public class Subject {
    private String id;
    private String name;
    public String getName() {
        return this.name;
The upper two files are in /db package  
If I autowire Repository in my Application class, I'm able to use it properly.
@SpringBootApplication
@Configuration
@EnableAutoConfiguration
@EnableMongoRepositories(basePackageClasses=Repository.class )
public class Application implements CommandLineRunner{
@Bean
public Service service() {
    return new Service();
@Autowired
private Repository repository;
@Override
public void run(String... args) throws Exception {
    repository.save(new Subject());
    Subject subject = repository.findByName("hello");
public static void main(String[] args) {
    SpringApplication.run(Application.class, args);
My Application class is in the root folder / . 
Basically, this gives me no error. But if I autowire this in a Service class like this 
public class Service {
@Autowired
private Repository repository;
public String get() {
    repository.findByName("hello");
    return "";
This gives me a null pointer exception in the line repository.findByName() . 
My Service class is in /service package . 
Why does it not behave same like in the application class?
What should I do differently to be able to use repository in the service class?  
What I have tried -

I tried annotating my Service class with @Service, @Repository, @Component, none of them worked.  
I tried adding annonation @ComponentScan(basePackageClasses = Service.name) for Application class, it didn't work . 
Any workaround is also fine -   
                How is your package  set up ? Is your Service class located in a different packing structure from your Application and Repository class ?
– s7vr
                Mar 1, 2017 at 20:25
                Yes, Service class is localted in a different package. Repository and Subject classes are in db package, Service is in service package and Application class is outside.
– Akshay Megharaj
                Mar 1, 2017 at 22:36
                You can annotate your Service with @Service annotation and if the Application class is at the root level package then your annotation should be picked up.
– s7vr
                Mar 1, 2017 at 22:45
Maybe it's because the Repository or Service hasn't been scanned by spring? have you annotated as @service, @repository or @component?
these works for me:
@SpringBootApplication
@EnableMongoRepositories
public class DemoApplication implements CommandLineRunner{
    @Autowired
    private Service service;
    @Override
    public void run(String... args) throws Exception {
        String subject = service.get();
        System.out.println("Hola" + subject);
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
@org.springframework.stereotype.Service
public class Service {
    @Autowired
    private Repository repository;
    public String get() {
        repository.findByName("hello");
        return "";
                Tried all the three annotations individually, none of them worked. Added all the annotations that I have for Application class, even this did not work.
– Akshay Megharaj
                Mar 1, 2017 at 22:45
        
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