Fix Micronaut @Cacheable Not Caching

In this tutorial, you'll learn about Fix Micronaut @Cacheable Not Caching. We cover key concepts, practical examples, and best practices.

The Problem

Method results annotated with @Cacheable are not cached. Each invocation executes the method again.

Quick Fix

Add cache dependency

Wrong:

<!-- No cache -->

Output:

No caching support

Right:

<dependency>
  <groupId>io.micronaut.cache</groupId>
  <artifactId>micronaut-cache-core</artifactId>
</dependency>

Output:

Caching enabled

Configure cache implementation

Wrong:

# No cache config
micronaut.cache.type=caffeine

Output:

No cache backend

Right:

micronaut:
  cache:
    type: caffeine
caffeine:
  max-size: 1000

Output:

Caffeine cache configured

Use @Cacheable correctly

Wrong:

@Cacheable("products")
public Product getProduct(Long id) { return expensiveCall(); }

Output:

Cached correctly

Right:

@Cacheable("products")
public Product getProduct(Long id) {
    return expensiveCall();
}

Output:

Result cached after first call

Prevention

• Add micronaut-cache-core dependency
• Configure cache type (caffeine, redis, etc.)
• Use @Cacheable on methods that should be cached

Common Mistakes with cache

1. Overlapping type class instances that cause GHC to reject the program with ambiguous dispatch errors
2. Non-exhaustive pattern matches that compile with warnings then crash at runtime
3. Misunderstanding that String is [Char] with poor performance for large text operations

These mistakes appear frequently in real-world MICRONAUT code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ

This quick fix is part of the DodaTech Spring & JVM ecosystem series. Built by the developers of Doda Browser, DodaZIP, and Durga Antivirus Pro.