RabbitTemplate for producing in Spring Boot - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What does this RabbitTemplate send() call do?

Consider this Spring Boot code snippet using RabbitTemplate:

rabbitTemplate.convertAndSend("myExchange", "myRoutingKey", "Hello World");

What happens when this line runs?

Spring Boot

rabbitTemplate.convertAndSend("myExchange", "myRoutingKey", "Hello World");

A Sends the message "Hello World" to the exchange named "myExchange" with routing key "myRoutingKey".

B Sends the message "Hello World" to the default exchange ignoring the routing key.

C Sends the message "Hello World" directly to a queue named "myRoutingKey".

D Sends the message "Hello World" to a queue named "myExchange".

💡 Hint

Remember that convertAndSend sends to an exchange with a routing key.

The convertAndSend method sends the message to the specified exchange using the routing key. It does not send directly to a queue unless the default exchange and routing key match a queue name.

📝 Syntax

intermediate

Which option correctly sends a Java object as JSON using RabbitTemplate?

You want to send a Java object as JSON message using RabbitTemplate. Which code snippet is correct?

A rabbitTemplate.send("exchange", "key", myObject);

B rabbitTemplate.convertAndSend("exchange", "key", myObject);

C rabbitTemplate.convertAndSend("exchange", "key", myObject.toString());

D rabbitTemplate.send("exchange", "key", new Message(myObject));

💡 Hint

convertAndSend automatically converts objects using configured message converters.

convertAndSend uses the message converter to serialize the object (e.g., to JSON) before sending. The send method requires a Message object, not a plain Java object.

🔧 Debug

advanced

Why does this RabbitTemplate call cause a runtime error?

Given this code:

rabbitTemplate.convertAndSend(null, "key", "msg");

What error will it cause?

Spring Boot

rabbitTemplate.convertAndSend(null, "key", "msg");

A MessageConversionException because message is null.

B IllegalArgumentException because routing key is invalid.

C No error, message sent to default exchange.

D NullPointerException because exchange name is null.

💡 Hint

RabbitTemplate handles null exchange name by sending to the default exchange.

RabbitTemplate treats a null exchange name as the default exchange (equivalent to empty string), so no error occurs and the message is sent to the default exchange using the routing key.

❓ state_output

advanced

What is the effect of this RabbitTemplate call with mandatory flag?

Consider this code snippet:

rabbitTemplate.setMandatory(true);
rabbitTemplate.convertAndSend("exchange", "wrongKey", "test");

Assuming no queue is bound with routing key "wrongKey", what happens?

Spring Boot

rabbitTemplate.setMandatory(true);
rabbitTemplate.convertAndSend("exchange", "wrongKey", "test");

A The message is sent but causes an exception in the application.

B The message is silently dropped by the broker.

C The message is sent to the default queue.

D The message is returned to the sender because no queue matches the routing key.

💡 Hint

Mandatory flag controls message return if no queue matches.

When mandatory is true, messages that cannot be routed to any queue are returned to the sender via a ReturnCallback.

🧠 Conceptual

expert

Which statement about RabbitTemplate's convertAndSend is true?

Select the correct statement about RabbitTemplate's convertAndSend method behavior.

A convertAndSend blocks the calling thread until the broker confirms message receipt if publisher confirms are enabled.

B convertAndSend automatically retries sending messages on failure without additional configuration.

C convertAndSend requires manual serialization of objects before sending.

D convertAndSend can only send String messages, not Java objects.

💡 Hint

Think about publisher confirms and synchronous behavior.

If publisher confirms are enabled, convertAndSend waits for broker acknowledgment before returning, blocking the thread. It does not retry automatically or require manual serialization.