Yes, this method that I have to use in the plugin has been deprecated by the Bukkit team, I will try to use an alternative for loading my configuration! 👍

If you have an idea and want to help me, don't hesitate to create a pull request.

@andris155: the deprecated method has been removed in the commit 0210d5a 👍
Hope that It will fix the error with your IDE (It works fine for me with Intellij Idea).