How to fix "Field ... required a bean of type ... that could not be found" exception Spring Boot

Question

I am working with spring boot tutorial from javabrains and everything was clear until putting CrudRepository inside project. Below you can find my main class:

package pl.springBootStarter.app;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class CourseApiDataApplication
{
    public static void main(String args[])
{
    SpringApplication.run(CourseApiDataApplication.class,args);
}
}

Service class:

package pl.springBootStarter.app.topic;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

@Service
public class TopicService
{
    @Autowired
    private TopicRepository topicRepository;

    private List<Topic> topics =  new ArrayList<>(Arrays.asList(
            new Topic("spring","spring framework", "spring framework dectription"),
            new Topic("sprin","spring framework", "spring framework dectription"),
            new Topic("spri","spring framework", "spring framework dectription")));

    public  List<Topic> getAllTopics()
    {
    //    return topics;
    List<Topic> t = new ArrayList<Topic>();
    topicRepository.findAll().forEach(t::add);
    return t;
    }

    public Topic getTopic (String id)
    {
        return   topics.stream().filter( t -> t.getId().equals(id)).findFirst().get();
    }

    public void addTopic(Topic topic) {
        topicRepository.save(topic);
    }

    public void updateTopic(Topic topic, String id)
    {
        topics.set(topics.indexOf(topics.stream().filter(t-> t.getId().equals(id)).findFirst().get()), topic);
    }

    public void deleteTopic(String id)
    {
        topics.remove(topics.stream().filter(t -> t.getId().equals(id)).findFirst().get());
    }
}

And Repository interface:

package pl.springBootStarter.app.topic;

import org.springframework.data.repository.CrudRepository;

public interface TopicRepository extends CrudRepository<Topic,String>
{

}

When I run the app there is a problem with injection of TopicRepository into topicRepository field in TopicService class. I get following error:

Error starting ApplicationContext. To display the conditions report re-       run your application with 'debug' enabled.
2019-05-01 10:33:52.206 ERROR 6972 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Field topicRepository in pl.springBootStarter.app.topic.TopicService required a bean of type 'pl.springBootStarter.app.topic.TopicRepository' that could not be found.

The injection point has the following annotations:
-    @org.springframework.beans.factory.annotation.Autowired(required=true)

What could be the reason that Spring cannot do the autowiring?

Answer 1

1 the main package is ex: com.demo.project and the remaining package naming should start with com.demo.project 2.For controller package will be like com.demo.project.controller 3.Simlarly for service all well com.demo.project.service

Answer 2

1. make sure that your Class has been managed, by adding @Component or @Service or @Controller such kind of annotation
2. make sure that you have added @ComponentScan (this might be done by Spring or other IoC framework.
3. make sure that your class path is correct
4. make sure you have no configuration class to manage your bean, some double database project might use a configuration to manage the different path visiting two different datasource.

Answer 3

in service class do: @Autowired(required=false)

Answer 4

In my cases, the necessary configuration from org.springframework.boot.autoconfigure.jdbc. has been excluded at SpringBootApplication, causing relevant bean not added properly. Check your main application java file and see if you can find following configuration in the exclusion list

import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration;

@SpringBootApplication(
    exclude = {
        DataSourceAutoConfiguration.class,                      // REMOVE THIS
        DataSourceTransactionManagerAutoConfiguration.class,    // REMOVE THIS
    }
)

and remove them from exclusion list.

Answer 5

Be sure the class is scanned by spring!

(this may help if that's the problem: Intellij Springboot problems on startup).

---

Optionally you may want to annotate TopicRepository as a @Repository.

@Repository
public interface TopicRepository extends CrudRepository<Topic,String>
{
}

See a demo code here: https://github.com/lealceldeiro/repository-demo

Answer 6

I got a similar message.

the thing was my main package was com.example and the package for other classes was com.xyz

so when I Changed the name of the package of other class to com.example.topic

i.e. finally The main package was com.example and the package for the other class was com.example.topic

A simple mistake, posting in case it helps anyone else.

Answer 7

I got a similar message and I was missing the @Service annotation in the Service class. Simple mistake, posting in case it helps anyone else.

Answer 8

For anybody who was brought here by googling the generic bean error message, but who is actually trying to add a feign client to their Spring Boot application via the @FeignClient annotation on your client interface, none of the above solutions will work for you.

To fix the problem, you need to add the @EnableFeignClients annotation to your Application class, like so:

@SpringBootApplication
// ... (other pre-existing annotations) ...
@EnableFeignClients // <------- THE IMPORTANT ONE
public class Application {

Answer 9

Spring cannot inject bean because it has not been created.

You have to instruct Spring to generate implementation of declared repository interfaces by using @EnableJpaRepositories(basePackages={"pl.springBootStarter.app"}) annotation on any of your configuration classes or class annotated with @SpringBootApplication. That should fix your problem.