This article is a record that I was addicted to when the Spring Boot application was internationalized in business, the message property file of a specific locale was not recognized. There are many detailed explanations of Spring Boot, so I will omit it.
In the case where the locale identification is included in the URI at the request of the other party (because it is not directly related to the problem but it is a hint of the addictive highway) ** English **: http://example.jp/en/foo ** Korea **: http://example.jp/ko/foo ** Taiwan **: http://example.jp/zh_tw/foo etc...
The bottom line is that the locale name in the list displayed by
locale -a should be the property file name. The problem was that the language code (lowercase) of the URI that was foreshadowed in the prerequisites was used as it was in the file name.
Wrong messages_** zh_tw **. Properties Positive messages _ ** zh_TW **. Properties
The local development environment was mac, but there was no problem recognizing files even in lowercase letters. Here was helpful as to why there was no problem with mac.
When I write the article again, it seems like it's just a mistake, but it was a problem that took some time to solve. I think it's a niche, but I hope it helps someone someday.