To retrieve all cache classes, make a GET request to /actuator/cache:

curl http://localhost:8081/actuator/cache

The JSON response body lists cache classes with their capacity and current level, as in the following example:

Response. 

{
  "cacheClasses": {
    "ALWAYS_STAY_IN_CACHE": {
      "capacity": 9223372036854775807,
      "level": 26,
      "href": "http://localhost:8081/actuator/cache/ALWAYS_STAY_IN_CACHE"
    },
    "DIGEST": {
      "capacity": 9223372036854775807,
      "level": 0,
      "href": "http://localhost:8081/actuator/cache/DIGEST"
    },
    "com.coremedia.cap.disk": {
      "capacity": 10737418240,
      "level": 0,
      "href": "http://localhost:8081/actuator/cache/com.coremedia.cap.disk"
    },
    "com.coremedia.cap.heap": {
      "capacity": 104857600,
      "level": 88905639,
      "href": "http://localhost:8081/actuator/cache/com.coremedia.cap.heap"
    },
    "java.lang.Object": {
      "capacity": 10000,
      "level": 107,
      "href": "http://localhost:8081/actuator/cache/java.lang.Object"
    }
  }
}

The cache classes ALWAYS_STAY_IN_CACHE and DIGEST are predefined classes with unlimited capacity. Cache class com.coremedia.cap.heap is used for internal caching in the Unified API, with capacity and level being rough estimates of the required heap memory in byte. Other cache classes may use different units for capacity and level, and many simply count the number of cached values like the cache class java.lang.Object, which is configured to hold up to 10,000 objects in this example.

The "href" links in the JSON response can be used to get information about a single cache class. These links are only present if the actuator endpoint is invoked over HTTP. Like many other endpoints, the cache endpoint may also be exposed and invoked over JMX, in which case the response will not contain such links.

To retrieve the capacity and level of a single cache class, make a GET request to /actuator/cache/<cacheClass>, for example:

curl http://localhost:8081/actuator/cache/com.coremedia.cap.heap

The response will look like

Response. 

{
  "capacity": 104857600,
  "level": 88905639
}

If the specified cache class is neither configured nor used, then the request will be answered with HTTP status code 404 (Not Found).