RabbitMQ integration basics in Spring Boot - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What happens when a Spring Boot RabbitMQ listener receives a message?

Consider a Spring Boot application with a RabbitMQ listener method annotated with @RabbitListener. What is the expected behavior when a message arrives in the queue?

Spring Boot

public class MessageListener {
    @RabbitListener(queues = "testQueue")
    public void receiveMessage(String message) {
        System.out.println("Received: " + message);
    }
}

A The method is called automatically with the message content as the argument.

B The method must be called manually after fetching the message from the queue.

C The message is ignored unless the method returns a value.

D The listener only logs the message but does not process it.

💡 Hint

Think about how Spring Boot handles methods annotated with @RabbitListener.

Spring Boot automatically calls methods annotated with @RabbitListener when a message arrives in the specified queue, passing the message content as the method argument.

📝 Syntax

intermediate

Which code snippet correctly declares a RabbitMQ queue bean in Spring Boot?

You want to declare a RabbitMQ queue named "myQueue" as a Spring bean. Which option is correct?

A

public Queue myQueue() {
    return new Queue("myQueue", false);
}

B

@Bean
public Queue myQueue() {
    return new Queue("myQueue");
}

C

@Bean
public Queue myQueue() {
    return new Queue();
}

D

@Bean
public Queue myQueue() {
    return new Queue("myQueue", true);
}

💡 Hint

Remember that @Bean annotation is needed and the constructor requires queue name and durability.

Option D correctly declares a durable queue bean with the @Bean annotation and proper constructor parameters.

🔧 Debug

advanced

Why does this Spring Boot RabbitMQ listener fail to receive messages?

Given the code below, why does the listener not receive any messages from the queue?

Spring Boot

public class Listener {
    @RabbitListener(queues = "orders")
    public void listen(String msg) {
        System.out.println("Order: " + msg);
    }
}

// Application properties:
spring.rabbitmq.host=localhost
spring.rabbitmq.port=5672

// No queue bean declared in configuration.

A The listener method signature is incorrect; it must return a value.

B The listener class must be annotated with @Component to be detected.

C The RabbitMQ host and port are missing in application properties.

D The queue 'orders' is not declared as a bean or created, so it does not exist in RabbitMQ.

💡 Hint

Check if the listener class is a Spring-managed bean.

The listener class must be annotated with @Component (or equivalent like @Service) to be detected by Spring's component scan. Without it, the @RabbitListener method is not processed and registered.

❓ state_output

advanced

What is the output when sending a message with RabbitTemplate?

Given the code below, what will be printed to the console?

Spring Boot

public class Sender {
    private final RabbitTemplate rabbitTemplate;

    public Sender(RabbitTemplate rabbitTemplate) {
        this.rabbitTemplate = rabbitTemplate;
    }

    public void send() {
        rabbitTemplate.convertAndSend("myExchange", "myRoutingKey", "Hello World");
        System.out.println("Message sent");
    }
}

// Assume exchange and queue are properly configured and bound.

A Message sent

B Hello World

C Error: exchange not found

D No output

💡 Hint

Focus on what the code explicitly prints.

The code prints "Message sent" after sending the message. The actual message is sent to RabbitMQ but not printed here.

🧠 Conceptual

expert

Which statement best describes the role of RabbitMQ exchanges in Spring Boot integration?

In Spring Boot RabbitMQ integration, what is the primary role of an exchange?

A An exchange stores messages until consumers retrieve them.

B An exchange is a client that sends messages to RabbitMQ.

C An exchange routes messages to queues based on routing keys and binding rules.

D An exchange encrypts messages before sending them to queues.

💡 Hint

Think about how messages find their way to queues.

Exchanges receive messages and route them to queues according to routing keys and bindings. They do not store or encrypt messages.