@Deprecated
  public StructObjectInspector initialize(ObjectInspector[] argOIs)
      throws UDFArgumentException {
    throw new IllegalStateException("Should not be called directly");
  }
Initialize this GenericUDTF. This will be called only once per instance.

@param argOIs
         An array of ObjectInspectors for the arguments
@return A StructObjectInspector for output. The output struct represents a
        row of the table where the fields of the stuct are the columns. The
        field names are unimportant as they will be overridden by user
        supplied column aliases.
ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDTF.java