Assess your understanding of Spring Boot caching concepts and performance optimization strategies. Enhance your practical knowledge of cache management, best practices, and techniques for efficient application performance in Spring Boot environments.
Which annotation would you use to automatically cache the result of a method in a Spring Boot application?
Explanation: @Cacheable is the correct annotation for caching method results automatically in Spring Boot. The distractors include '@Catchable' and '@Cachable', which are both misspellings. '@CachePut' is used for updating cached values, not for automatically caching method results.
If you want to remove a specific item from the cache when a method is called, which annotation should you use?
Explanation: @CacheEvict allows you to remove specific items from the cache based on method invocation. '@CacheInsert' and '@CacheRemove' are not standard annotations, and '@EvictCache' is a made-up option. Only '@CacheEvict' serves this purpose in caching management.
What annotation must you add to a configuration class to enable caching across a Spring Boot application?
Explanation: @EnableCaching is required to activate caching at an application-wide level in Spring Boot. The alternatives '@EnableCache' and '@EnableCaches' are close but incorrect, while '@CacheEnable' is not a valid annotation. Only '@EnableCaching' enables this functionality.
Which built-in caching solution can be used by default in Spring Boot without extra dependencies for simple caching scenarios?
Explanation: ConcurrentMapCache is the default built-in cache implementation for simple caching in Spring Boot and requires no additional setup. 'RedisCache' and 'Ehcache' require extra dependencies, while 'MemCached' is not directly available by default. Only 'ConcurrentMapCache' fits the description.
How does caching improve the performance of a Spring Boot application in the case of repeated data queries?
Explanation: Caching allows data to be stored in memory, which speeds up repeated data access and decreases the load on databases. Increasing threads does not directly relate to caching, while compressing responses and delaying tasks are unrelated to cache performance. Only storing in-memory data reduces query times using caching.
In Spring Boot, if you need to cache the result of a method only when a specific condition is true, which attribute can you use in the @Cacheable annotation?
Explanation: The 'condition' attribute allows for conditional caching based on a provided expression. 'Unless' works in the opposite way by vetoing the caching, and 'when' and 'ifPresent' are not valid attributes in this annotation. Only 'condition' directly enables selective caching based on method input or output.
What is a common approach to prevent frequently changing data from polluting the cache in a Spring Boot application?
Explanation: It is best to avoid caching data that changes frequently to prevent cache pollution and stale data. Setting a longer timeout can worsen the issue, increasing pool size only affects connections and not caching, and disabling garbage collection is irrelevant. Avoiding caching dynamic data is the best solution.
How can you define a custom key for a cached method in Spring Boot, for example, to combine multiple method arguments?
Explanation: The 'key' attribute in @Cacheable lets you define complex cache keys based on method parameters or expressions. Prefixing via cache manager, annotating arguments, or changing filenames does not customize cache keys at the method level. The 'key' attribute is specifically designed for this purpose.
What is the simplest way to ensure a specific method in a Spring Boot service is never cached?
Explanation: If a method lacks the @Cacheable annotation, it will not be cached by the framework. Assigning a null cache name does not prevent caching, and marking it as deprecated is for documentation. Setting timeout to zero might not disable caching depending on the provider, so omitting the annotation is most reliable.
Which general technique is recommended for tracking cache performance and identifying bottlenecks in a Spring Boot application?
Explanation: Enabling statistics on the cache manager allows you to gather useful data on hit and miss rates, helping to detect performance bottlenecks. Increasing heap size is not always effective, using static pages bypasses backend caching, and disabling logging eliminates useful diagnostic information. Only monitoring cache statistics directly improves cache analysis.