private boolean isExternalTableChanged (Map<String, String> tblProp, boolean isTransactional, boolean isExt, boolean isTableTypeChanged) {
    if (isTableTypeChanged && tblProp != null && tblProp.getOrDefault(hive_metastoreConstants.TABLE_IS_TRANSACTIONAL, "false").equalsIgnoreCase("true") || isTransactional) {
      isExt = false;
    }
    return isExt;
  }
This api is used to determine where to create acid tables are not.
if the default table type is set to external, then create transactional table should result in acid tables,
else create table should result in external table.
ql/src/java/org/apache/hadoop/hive/ql/parse/SemanticAnalyzer.java