private <T> List<T> convertList(List<T> dnList) {
    return (dnList == null) ? null : Lists.newArrayList(dnList);
  }
Makes shallow copy of a list to avoid DataNucleus mucking with our objects.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java