So, I am in the process of working on an ID auto assigner for my mod. However, I want to be able to change a value of the configuration file through code.

 

Example:

I want to be able to change this configuration property "autoAssign=true" to "autoAssign=false"

I would try something like this (it's not tested!):

config.getCategory(Configuration.CATEGORY_GENERAL).get("autoAssign").set(false);

and then save it:

config.save();

I would just like to report that mnn's solution works.  He got the config syntax wrong, but there is a set method that works for most data types.

 

I wanted to read in an integer array, then sort it, in order to take advantage of reading this array later in a fast method.  So I figured I might as well sort the array and save it back to the config.  Here's the solution:

 

int[] white = config.get("WorldGen","dimensionWhitelistList", new int[] {0}).getIntList(); //read the values, supplying defaults
		int[] black = config.get("WorldGen","dimensionBlacklistList", new int[] {-1,1}).getIntList();

		Arrays.sort(white); //sort
		Arrays.sort(black);

		String a=Arrays.toString(white);
		String whitestring[]=a.substring(1,a.length()-1).split(", "); //have to convert to a string array in order to write
		String b=Arrays.toString(black);
		String blackstring[]=b.substring(1,b.length()-1).split(", ");

		config.get("WorldGen","dimensionWhitelistList", new int[] {0}).set(whitestring); //default values here are irrelevant, but required in order to retrieve the config Property
		config.get("WorldGen","dimensionBlacklistList", new int[] {-1,1}).set(blackstring);