How are you defining your MessageSource?
Typically you would set the base in that configuration and then have a file somewhere like
messages_en_US.properties (I chose US just because I have no idea what language that is
)
which would in turn contain
DigestAuthenticationFilter.usernameNotFound=Utilisateur {0} non paramétré en base
Now when you access it you would do so like this:
Now that last
String argument you provided is a default message which will be used if the lookup fails. In this case that String will be printed as is (no replacement is done) which is the behavior you are seeing.
for example