@Override
  public synchronized Object getOrDefault(Object key, Object defaultValue) {
    if (interned != null) return interned.getOrDefault(key, defaultValue);
    else return super.getOrDefault(key, defaultValue);
  }
**********   Public API of java.util.Hashtable   ***********
common/src/java/org/apache/hadoop/hive/common/CopyOnFirstWriteProperties.java