code: private void processUDF(UDFTypeType udf)
     {
        FieldTypeClass fieldType = FIELD_TYPE_MAP.get(udf.getSubjectArea());
        if (fieldType != null)
        {
           UserFieldDataType dataType = UserFieldDataType.getInstanceFromXmlName(udf.getDataType());
           String name = udf.getTitle();
           FieldType field = addUserDefinedField(fieldType, dataType, name);
           if (field != null)
           {
              m_fieldTypeMap.put(udf.getObjectId(), field);
           }
        }
     }
docs: Process an individual UDF.
  
  @param udf UDF definition