Spring Boot could not autowire and run - spring

Question

I am unable to run the attached Spring Boot sampler application. It has an AMQP starter, requiring RabbitMQ. Fundamentally, it is a simple application that just sends a message to a RabbitMQ Exchange with a queue bound to it. I get the following error:
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.company.messaging.MessageDeliveryManager com.company.exec.Application.messageDeliveryManager; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.company.messaging.MessageDeliveryManager] 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)}
Application.java
package com.company.exec;
#SpringBootApplication
public class Application implements CommandLineRunner {
#Autowired
MessageDeliveryManager messageDeliveryManager;
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
public void run(String... args) throws Exception {
messageDeliveryManager.sendMessage(String message);
}
}
MessageDeliveryManager.java
package com.company.messaging;
public interface MessageDeliveryManager {
void sendMessage(String message);
}
MessageDeliveryImpl.java
package com.company.messaging;
public class MessageDeliveryManagerImpl implements MessageDeliveryManager {
#Value("${app.exchangeName}")
String exchangeName;
#Value("${app.queueName}")
String queueName;
#Autowired
RabbitTemplate rabbitTemplate;
#Bean
Queue queue() {
return new Queue(queueName, false);
}
#Bean
DirectExchange exchange() {
return new DirectExchange(exchangeName);
}
#Bean
Binding binding(Queue queue, DirectExchange exchange) {
return BindingBuilder.bind(queue).to(exchange).with(queueName);
}
public void sendMessage(String message) {
rabbitTemplate.send(queueName, message);
}
}
I would really appreciate if someone can review and provide a suggestion on what I am doing wrong.

Answer 1

Since you have a package tree like this:
com.company.exec
com.company.messaging
and just use a default #SpringBootApplication, it just doesn't see your MessageDeliveryManager and its implementation. That's because #ComponentScan (the meta-annotation on the #SpringBootApplication) does a scan only for the current package and its subpackages.
To make it worked you should add this:
#SpringBootApplication
#ComponentScan("com.company")
Or just move your Application to the root package - com.company.