code: public static <MK, K, V> AtomicMap<K, V> getAtomicMap(Cache<MK, ?> cache, MK key, boolean createIfAbsent) {
        return (AtomicMap<K, V>) getMap((Cache<MK, Object>) cache, key, createIfAbsent, false);
     }
docs: Retrieves an atomic map from a given cache, stored under a given key.
  
  @param cache          underlying cache
  @param key            key under which the atomic map exists
  @param createIfAbsent if true, a new atomic map is created if one doesn't exist; otherwise null is returned if the
  map didn't exist.
  @param <MK>           key param of the cache
  @param <K>            key param of the AtomicMap
  @param <V>            value param of the AtomicMap
  @return an AtomicMap, or null if one did not exist.