protected void init(
      List<ObjectInspector> ois, byte separator,
      LazyObjectInspectorParameters lazyParams) {
    this.separator = separator;
    this.lazyParams = lazyParams;
    this.ois = new ArrayList<ObjectInspector>();
    this.ois.addAll(ois);
  }
LazyUnionObjectInspector works on union data that is stored in LazyUnion.

Always use the {@link LazyObjectInspectorFactory} to create new
ObjectInspector objects, instead of directly creating an instance of this
class.
serde/src/java/org/apache/hadoop/hive/serde2/lazy/objectinspector/LazyUnionObjectInspector.java