UnsatisfiedDependencyException: Error creating bean with name

The ClientRepository should be annotated with @Repository tag. With your current configuration Spring will not scan the class and have knowledge about it. At the moment of booting and wiring will not find the ClientRepository class.

EDIT If adding the @Repository tag doesn’t help, then I think that the problem might be now with the ClientService and ClientServiceImpl.

Try to annotate the ClientService (interface) with @Service. As you should only have a single implementation for your service, you don’t need to specify a name with the optional parameter @Service("clientService"). Spring will autogenerate it based on the interface’ name.

Also, as Bruno mentioned, the @Qualifier is not needed in the ClientController as you only have a single implementation for the service.

ClientService.java

@Service
public interface ClientService {

    void addClient(Client client);
}

ClientServiceImpl.java (option 1)

@Service
public class ClientServiceImpl implements ClientService{

    private ClientRepository clientRepository;

    @Autowired
    public void setClientRepository(ClientRepository clientRepository){
        this.clientRepository=clientRepository;
    }

    @Transactional
    public void addClient(Client client){
        clientRepository.saveAndFlush(client);
    }
}

ClientServiceImpl.java (option 2/preferred)

@Service
public class ClientServiceImpl implements ClientService{

    @Autowired
    private ClientRepository clientRepository;

    @Transactional
    public void addClient(Client client){
        clientRepository.saveAndFlush(client);
    }
}

ClientController.java

@Controller
public class ClientController {
    private ClientService clientService;

    @Autowired
    //@Qualifier("clientService")
    public void setClientService(ClientService clientService){
        this.clientService=clientService;
    }

    @RequestMapping(value = "registration", method = RequestMethod.GET)
    public String reg(Model model){
        model.addAttribute("client", new Client());
        return "registration";
    }

    @RequestMapping(value = "registration/add", method = RequestMethod.POST)
    public String addUser(@ModelAttribute Client client){
        this.clientService.addClient(client);
    return "home";
    }
}