# Nothing in application.yml selects a provider. Something still chose one.

spring.cache.type          : (not set)
resolved CacheManager bean : org.springframework.cache.caffeine.CaffeineCacheManager

Caffeine is on this module's classpath because a later chapter needs TTL and
size bounds. That single dependency moved every cache in the application off
the ConcurrentHashMap-backed 'simple' provider, because Boot walks a fixed
detection order and stops at the first provider it finds:

  1 Generic      2 JCache      3 Hazelcast   4 Infinispan   5 Couchbase
  6 Redis        7 Caffeine    8 Cache2k     9 Simple

Nothing logs the decision at INFO. If a cache suddenly starts expiring
entries, or stops, look at what changed in the dependency tree.