Dead letter queues in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a dead letter queue in Spring Boot.

Spring Boot

Queue deadLetterQueue() {
    return new Queue("[1]", true);
}

Drag options to blanks, or click blank then click option'

AmainQueue

BmyDeadLetterQueue

CprocessingQueue

DretryQueue

Attempts:

3 left

💡 Hint

Common Mistakes

Using the main queue name instead of a dead letter queue name.

Using a retry queue name which is different from dead letter queue.

The dead letter queue is usually named distinctly, here "myDeadLetterQueue" is the correct name.

2fill in blank

medium

Complete the code to bind the dead letter queue to the dead letter exchange.

Spring Boot

Binding deadLetterBinding(Queue deadLetterQueue, DirectExchange deadLetterExchange) {
    return BindingBuilder.bind(deadLetterQueue).to(deadLetterExchange).with("[1]");
}

Drag options to blanks, or click blank then click option'

AretryRoutingKey

BprocessingRoutingKey

CmainRoutingKey

DdeadLetterRoutingKey

Attempts:

3 left

💡 Hint

Common Mistakes

Using the main routing key instead of the dead letter routing key.

Using the retry routing key which is unrelated.

The dead letter queue is bound using the dead letter routing key.

3fill in blank

hard

Fix the error in the queue declaration to enable dead letter exchange support.

Spring Boot

Map<String, Object> args = new HashMap<>();
args.put("[1]", "deadLetterExchange");
Queue queue = new Queue("mainQueue", true, false, false, args);

Drag options to blanks, or click blank then click option'

Ax-dead-letter-exchange

Bx-message-ttl

Cx-max-length

Dx-priority

Attempts:

3 left

💡 Hint

Common Mistakes

Using TTL or max length keys instead of dead letter exchange key.

Forgetting to set the dead letter exchange argument.

The argument key "x-dead-letter-exchange" tells the queue which exchange to use for dead letters.

4fill in blank

hard

Fill both blanks to configure a queue with dead letter exchange and dead letter routing key.

Spring Boot

Map<String, Object> args = new HashMap<>();
args.put("[1]", "deadLetterExchange");
args.put("[2]", "deadLetterRoutingKey");
Queue queue = new Queue("mainQueue", true, false, false, args);

Drag options to blanks, or click blank then click option'

Ax-dead-letter-exchange

Bx-message-ttl

Cx-dead-letter-routing-key

Dx-max-length

Attempts:

3 left

💡 Hint

Common Mistakes

Using TTL or max length keys instead of dead letter keys.

Mixing up the routing key and exchange keys.

Both keys are needed: one for the dead letter exchange and one for the routing key.

5fill in blank

hard

Fill all three blanks to create a dead letter queue, dead letter exchange, and bind them with a routing key.

Spring Boot

Queue deadLetterQueue() {
    return new Queue("[1]", true);
}

DirectExchange deadLetterExchange() {
    return new DirectExchange("[2]");
}

Binding deadLetterBinding() {
    return BindingBuilder.bind(deadLetterQueue()).to(deadLetterExchange()).with("[3]");
}

Drag options to blanks, or click blank then click option'

AmyDeadLetterQueue

BdeadLetterExchange

CdeadLetterRoutingKey

DmainQueue

Attempts:

3 left

💡 Hint

Common Mistakes

Using main queue or unrelated names for dead letter components.

Mismatching routing key and binding key.

The dead letter queue, exchange, and routing key must be named consistently to work together.