@Override
    protected <K, V> Cache<K, V> createCache(String name) throws CacheException {
        return new HashMapCache<>(name);
    }
Returns HashMap-backed cache instances for testing only.  NEVER use this in production, as it would cause
memory leaks since HashMaps retain strong references.

@since 1.0
core/src/test/java/org/apache/shiro/config/HashMapCacheManager.java