How to make a String config?

I can't really find much documentation on Configs, especially strings...

To put simply, I want to have it so that a user will set the information of the item.

When I do something like a boolean, I do it like so:

public static boolean disableUberium;
public static boolean disabled = false;

	final String UBERIUM = Main.config.CATEGORY_GENERAL + Main.config.CATEGORY_SPLITTER + "Materials";
	Main.config.addCustomCategoryComment(UBERIUM, "Disable materials here");
	this.disableUberium = Main.config.get(UBERIUM, "I don't like being OP", disabled).getBoolean(disabled);
	if(Main.config.hasChanged()){
		Main.config.save();
	}

So if I was to do a string how would I do it?

I thought it would be like this, but then I get lost:

public static String description;
	final String DESC = Main.config.CATEGORY_GENERAL + Main.config.CATEGORY_SPLITTER + "Materials";
	this.description = Main.config.get(DESC, "default text").getString();
	if(Main.config.hasChanged()){
		Main.config.save();
	}

But it doesn't seem to work, any ideas?

(default text is what the description of the item would be)