private static void digest(MessageDigest md, Object obj) {
        if (obj == null) {
            return;
        }
        try (ObjectOutput out = new ObjectOutputStream(new TagOutputStream(md))) {
            out.writeObject(obj);
        } catch (IOException ex) {
            // ignore close exception
        }
        // ignore close exception
    }
Updates a digest with an object.
@param md the digest to update
@param obj the object
standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/properties/Digester.java