public static String getStandardUnionTypeName(UnionObjectInspector uoi) {
    StringBuilder sb = new StringBuilder();
    sb.append(serdeConstants.UNION_TYPE_NAME + "<");
    List<ObjectInspector> ois = uoi.getObjectInspectors();
    for(int i = 0; i < ois.size(); i++) {
      if (i > 0) {
        sb.append(",");
      }
      sb.append(ois.get(i).getTypeName());
    }
    sb.append(">");
    return sb.toString();
  }
Returns a deep copy of the Object o that can be scanned by a
StandardObjectInspector returned by getStandardObjectInspector(oi).
serde/src/java/org/apache/hadoop/hive/serde2/objectinspector/ObjectInspectorUtils.java