@Override
  public boolean isUndoable() {
    // Alters and replacements are not undoable if they've taken effect already. They are retriable though.
    // Creates are undoable, but we cannot differentiate between creates, alters and replacements from a Command level.
    return false;
  }
Trivial ctor to support Writable reflections instantiation
do not expect to use this object as-is, unless you call
readFields after using this ctor
hcatalog/webhcat/java-client/src/main/java/org/apache/hive/hcatalog/api/repl/commands/ImportCommand.java