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The Spring message feature used in the example view supports a limited form of internationalization. The browser's Accept-Language header can be used to favor a language-specific message file that will be used in place of the default file. For example, a file named messages/messages_fr.properties would be used for a French locale. As far as we know, Spring limits this to a single locale that either has a match or falls back to the default, which does not allow for preference-based selection.
Have a look at the Messages Translation page to find out how to download existing or create new translations of the IdP's messages.
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