Solution - No Qualifying Bean of Type Found for Dependency

The error message "No qualifying bean of a type found for dependency" typically arises when using the Spring framework, and it means that Spring's IoC container cannot find an appropriate bean to inject for a particular dependency. In this post, we will share some common solutions to this error.

Why Does This Error Occur?

The error occurs when:

• You try to @Autowired (or inject) a bean, but Spring doesn't have any instance of that bean in its context.
• There are multiple beans of the same type in the Spring context, and Spring doesn't know which one to inject.
• The bean or the configuration class is not scanned by Spring's component scanner.

How to Fix the Error?

Solution 1: Check Component Scanning

Ensure that the class you want to inject is annotated with @Component or another stereotype annotation like @Service, @Repository, or @Controller.

Ensure your @SpringBootApplication or @ComponentScan annotation is in the right package to scan the package containing your beans.

Solution 2: Explicitly Define the Bean

In case auto scanning is not picking up your component, you can define the bean explicitly in a Configuration class:

@Configuration
public class AppConfig {
    @Bean
    public MyBean myBean() {
        return new MyBean();
    }
}

Solution 3: Use Qualifier for Multiple Beans

If there are multiple beans of the same type, you can use the @Qualifier annotation to specify which bean to autowire.

@Autowired
@Qualifier("beanName")
private MyBean myBean;

If you are still getting the same issue then try the below solutions as well:

Check Profiles:

If you're using Spring Profiles, ensure that the right profile is active if the bean is defined under a specific profile.

External Libraries:

If the bean you're trying to inject is part of an external library, ensure that the library is correctly added as a dependency, and its components are being scanned.

Constructor Injection:

Prefer constructor injection over field injection. It's more evident when a class has dependencies, and it can also help avoid some issues related to circular dependencies.

@Service
public class MyService {
    private final MyBean myBean;

    @Autowired
    public MyService(MyBean myBean) {
        this.myBean = myBean;
    }
}

Check for Version Conflicts:

Ensure that you don't have conflicting versions of Spring or related libraries. Dependency conflicts can sometimes cause unexpected behaviors.

Check the Error Message:

The error message often provides the exact bean type it's trying to inject. Double-check that you haven't made a typo or incorrect package reference.

By thoroughly going through these checks and understanding the root cause, you can address the "No qualifying bean of a type found for dependency" error and ensure your Spring components wire up correctly.