diacritics deploying Java EE app

I have an app that is sending mail via GlassFish JavaMail Session.

I have localhost and production server, when I deploy the app on localhos开发者_StackOverflowt - development - everything is ok, but on production, the letters in the e-mail with diacritics are not displayed properly, but as ??? question marks. The acute letters works:áéóíú, but the caron ščřďťňž don't. Do you know where I should start to find the solution? Both are linux machines - one is Arch the other Debian.

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Perhaps the encoding on one machine is utf-8 and the other is e.g. iso-8859-1?