SpringBoot - UTF-8 Doesnt work in messages.properties

In my case, I forgot messageSource.setDefaultEncoding("UTF-8"), see here.

To read any file in the UTF-8 encoding it must be created in the UTF-8 before.

Use some editor which supports encoding switching. Or create that file from IDE with encoding option for properties files. E.g. IDEA: http://blog.jetbrains.com/idea/2013/03/use-the-utf-8-luke-file-encodings-in-intellij-idea/