@CacheEvict for invalidation in Spring Boot - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What happens when @CacheEvict is used with allEntries=true?

Consider a Spring Boot service method annotated with @CacheEvict(value = "items", allEntries = true). What is the effect on the cache when this method is called?

Spring Boot

public class ItemService {

  @CacheEvict(value = "items", allEntries = true)
  public void clearAllItemsCache() {
    // method logic
  }
}

A A new cache entry is added instead of removing any entries.

B Only the cache entry corresponding to the method's parameters is removed.

C The cache is not affected because allEntries=true disables eviction.

D All entries in the 'items' cache are removed when the method is called.

💡 Hint

Think about what 'allEntries=true' means for cache eviction.

Setting allEntries=true tells Spring to remove all entries from the specified cache, not just the one related to the method parameters.

📝 Syntax

intermediate

Which @CacheEvict annotation syntax correctly evicts a cache entry by key?

You want to evict a cache entry with a specific key passed as a method parameter named 'id'. Which annotation syntax is correct?

Spring Boot

public class UserService {

  @CacheEvict(value = "users", key = "#id")
  public void removeUser(Long id) {
    // method logic
  }
}

A "id"

B "#id"

C "$id"

D "{id}"

💡 Hint

Spring SpEL expressions use # to reference method parameters.

The key attribute uses Spring Expression Language (SpEL). To refer to the method parameter 'id', use #id.

🔧 Debug

advanced

Why does @CacheEvict not remove the cache entry as expected?

Given the code below, the cache entry is not removed after calling deleteProduct(5L). What is the most likely cause?

Spring Boot

public class ProductService {

  @CacheEvict(value = "products", key = "#productId")
  public void deleteProduct(Long id) {
    // deletion logic
  }
}

A The key expression uses 'productId' but the method parameter is named 'id'.

B The cache name 'products' is misspelled.

C The method must return a value to trigger cache eviction.

D The @CacheEvict annotation requires allEntries=true to work.

💡 Hint

Check if the key expression matches the method parameter name.

The key expression #productId does not match the method parameter id. This mismatch causes Spring to look for a non-existent parameter, so eviction fails.

❓ state_output

advanced

What is the cache state after calling a method with @CacheEvict(allEntries=true) and before method execution?

Consider a method annotated with @CacheEvict(value = "orders", allEntries = true, beforeInvocation = true). What is the state of the 'orders' cache when the method throws an exception during execution?

Spring Boot

public class OrderService {

  @CacheEvict(value = "orders", allEntries = true, beforeInvocation = true)
  public void cancelAllOrders() {
    throw new RuntimeException("Failure");
  }
}

A The 'orders' cache is cleared before the exception is thrown.

B The 'orders' cache remains unchanged because the method failed.

C Only some entries are removed depending on the exception.

D The cache eviction happens after the exception, so no entries are removed.

💡 Hint

Consider the effect of beforeInvocation=true on eviction timing.

With beforeInvocation=true, cache eviction happens before the method runs. So even if the method throws an exception, the cache is already cleared.

🧠 Conceptual

expert

Which statement best describes the use of @CacheEvict in Spring Boot?

Select the most accurate description of how @CacheEvict works in Spring Boot caching.

A @CacheEvict only works with methods that return a value and cannot clear all cache entries.

B @CacheEvict automatically updates cache entries with new values after method execution.

C @CacheEvict removes cache entries either by key or all entries, and can be configured to run before or after method execution.

D @CacheEvict disables caching for the annotated method but does not remove existing cache entries.

💡 Hint

Think about eviction timing and scope options.

@CacheEvict is designed to remove cache entries. It can remove specific keys or all entries and supports eviction before or after the method runs.