protected String getStringValue(DeferredObject[] arguments, int i, Converter[] converters)
      throws HiveException {
    Object obj;
    if ((obj = arguments[i].get()) == null) {
      return null;
    }
    return converters[i].convert(obj).toString();
  }
Some information may be set during initialize() which needs to be saved when the UDF is copied.
This will be called by FunctionRegistry.cloneGenericUDF()
ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDF.java