Spring Boot Spring Boot Caching and Messaging 3

Question 1

Which interface in Spring Cache abstraction allows you to define a custom cache key generation strategy?

Accepted Answer

KeyGenerator

Answer

Implementing `KeyGenerator` and registering it as a bean lets you override default key generation for `@Cacheable`, `@CachePut`, and `@CacheEvict`.

Question 2

What is the default `CacheManager` Spring Boot auto-configures when no cache provider dependency is on the classpath?

Accepted Answer

ConcurrentMapCacheManager

Answer

When no cache-specific dependency is detected, Spring Boot auto-configures `ConcurrentMapCacheManager`, which stores entries in JVM heap memory.

Question 3

Which property configures the name of the Kafka consumer group for a Spring Boot application?

Accepted Answer

spring.kafka.consumer.group-id

Answer

`spring.kafka.consumer.group-id` sets the consumer group ID, which Kafka uses to track offsets and distribute partitions among group members.

Question 4

What does setting `spring.rabbitmq.listener.simple.acknowledge-mode=manual` require of the message listener?

Accepted Answer

The listener must explicitly acknowledge or reject each message using Channel

Answer

Manual acknowledgment mode requires the listener to call `channel.basicAck()` or `channel.basicNack()` to confirm message processing to RabbitMQ.

Question 5

What Spring Boot caching annotation would you use to conditionally cache results based on a SpEL expression?

Accepted Answer

@Cacheable with the `condition` attribute

Answer

`@Cacheable(condition = "#id > 0")` uses a SpEL expression to decide at runtime whether the result should be stored in or retrieved from the cache.

Spring Boot Practice Test