Ilość pozycji w configu

int count = config.getConfigurationSection("test").getKeys(false /* deep? */).size();

Cytat

If deep is set to true, then this will contain all the keys within any child ConfigurationSections (and their children, etc). These will be in a valid path notation for you to use.
If deep is set to false, then this will contain only the keys of any direct children, and not their own children.

Problem został rozwiązany.