Description:

All i18n languages seem not to be supported by api call despite that we supply the messages.property file

Is there a documentation about it?

• Tested Chinese (zh -> file zh_CN)
  • https://www.w3.org/International/O-charset-lang.html
  • https://www.loc.gov/standards/iso639-2/php/English_list.php

Technical analysis:

The LocaleMapper transforms the whole locale to lowercase and thus also transforms the region (which is intended to be in uppercase):
https://github.com/Talend/component-runtime/blob/a63271daab9dbadb82b864d70f3580a9e45bd821/component-server-parent/component-server/src/main/java/org/talend/sdk/component/server/service/LocaleMapper.java#L61

For testing, changed a Messages properties named Messages_zh_CN.properties to Message_zh_cn.properties and the bundle was found.