Auto configuration is one of the most important features of Spring Boot. The AutoConfiguration endpoint (/actuator/conditions) exposes the details related to auto configuration. It shows both positive matches and negative matches, with details about why a particular auto configuration succeeded or failed.

The following extract shows some of the positive matches from the response:

"positiveMatches": {
  "AuditAutoConfiguration#auditListener": [
   {
     "condition": "OnBeanCondition",
     "message": "@ConditionalOnMissingBean (types:     
      org.springframework.boot.actuate.audit.
      listener.AbstractAuditListener; SearchStrategy: all) did not find 
      any beans"
   }
 ],
 "AuditAutoConfiguration#authenticationAuditListener": [
 {
   "condition": "OnClassCondition",
   "message": "@ConditionalOnClass found required class
   'org.springframework.security.authentication.
   event.AbstractAuthenticationEvent'"
 },

The following extract shows some of the negative matches from the response:

"negativeMatches": {
  "CacheStatisticsAutoConfiguration.
   CaffeineCacheStatisticsProviderConfiguration": [
 {
   "condition": "OnClassCondition",
   "message": "@ConditionalOnClass did not find required class  
   'com.github.benmanes.caffeine.cache.Caffeine'"
 }
 ],
   "CacheStatisticsAutoConfiguration.
   EhCacheCacheStatisticsProviderConfiguration": [
 {
   "condition": "OnClassCondition",
   "message": "@ConditionalOnClass did not find required classes
   'net.sf.ehcache.Ehcache',   
   'net.sf.ehcache.statistics.StatisticsGateway'"
 }
 ],

All of these details are very useful in order to debug auto configuration.