Spring Boot Annotation #Autowired of Service fails - spring

Question

I'm trying to use #Autowired annotation for a Service class in Spring Boot application, but it keeps throwing No qualifying bean of type exception. However, if I change the service class to a bean, then it works fine. This is my code:
package com.mypkg.domain;
#Service
public class GlobalPropertiesLoader {
#Autowired
private SampleService sampleService;
}
package com.mypkg.service;
#Service
public class SampleService{
}
And this is my SpringBoot class:
package com.mypkg;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.data.rest.webmvc.config.RepositoryRestMvcConfiguration;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Import;
#SpringBootApplication
#EnableJpaRepositories
#Import(RepositoryRestMvcConfiguration.class)
#EnableTransactionManagement
public class TrackingService {
private static final Logger LOGGER = LoggerFactory.getLogger(TrackingService.class);
static AnnotationConfigApplicationContext context;
public static void main(String[] args) throws Exception {
SpringApplication.run(TrackingService.class, args);
context = new AnnotationConfigApplicationContext();
context.refresh();
context.close();
}
}
When I try to run this, I get the following exception:
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.mypkg.service.SampleService] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {#org.springframework.beans.factory.annotation.Autowired(required=true)}
But when I remove the #Service annotation from the SampleService class, and add it as a bean in my AppConfig class as below, it works fine:
#Configuration
public class AppServiceConfig {
public AppServiceConfig() {
}
#Bean(name="sampleService")
public SampleService sampleService(){
return new SampleService();
}
}
The classes are in different packages. I am not using #ComponentScan. Instead, I'm using #SpringBootApplication which does that automatically. However, I tried with ComponentScan as well but that didn't help.
What am I doing wrong here?

Answer 1

You are using two ways to build a Spring's bean. You just need to use one of them.
#Service over the POJO
#Service
public class SampleService
#Bean in the configuration class which must be annotated with #Configuration
#Bean
public SampleService sampleService(){
return new SampleService();
}
#Autowired is resolved by class type then #Bean(name="sampleService") is not needed is you have only one bean with that class type.
EDIT 01
package com.example
#SpringBootApplication
public class Application implements CommandLineRunner {
public static void main(String... args) {
SpringApplication.run(Application.class);
}
#Autowired
private UserRepository userRepository;
#Autowired
private UserService userService;
#Override
public void run(String... strings) throws Exception {
System.out.println("repo " + userRepository);
System.out.println("serv " + userService);
}
}
package com.example.config
#Configuration
public class AppConfig {
#Bean
public UserRepository userRepository() {
System.out.println("repo from bean");
return new UserRepository();
}
#Bean
public UserService userService() {
System.out.println("ser from bean");
return new UserService();
}
}
package com.example.repository
#Service
public class UserRepository {
#PostConstruct
public void init() {
System.out.println("repo from #service");
}
}
package com.example.service
#Service
public class UserService {
#PostConstruct
public void init() {
System.out.println("service from #service");
}
}
Using this code you can comment the AppConfig class and then you will see how UserRepository and UserService are autowired. After that comment #Service in each class and un-comment AppConfig and classes will be autowired too.