public Set<Entry<K, V>> entrySet() {
        final Map<K, V> map = ref != null ? ref.get() : null;
        return map != null ? map.entrySet() : Collections.emptySet();
    }
Produces the cache entry set.
@return the cache entry set
standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/properties/SoftCache.java