@Override
    public String toString() {
      return "HCatClient: thread: " + Thread.currentThread().getId() + " users=" + users.get()
        + " expired=" + expiredFromCache + " closed=" + isClosed;
    }
Close the underlying objects irrespective of whether they are in use or not.
hcatalog/core/src/main/java/org/apache/hive/hcatalog/common/HiveClientCache.java