How should resources in a compiled jar be accessed?

First of all, I have read through many S.O. questions regarding this topic and I have tried the things suggested in them.

Here is my situation. I am writing a Java app using the Processing framework and I'm in the final stages where I need to begin thinking about packaging the app. A jar file that is executable from the command line is what I'm attempting to build using the Export feature in Eclipse.

The structure of my project looks like this:

src/
   multiple packages/
libs/
   jar files and natives
data/
   fonts and images
config/
   json files

When I export the jar file and uzip the jar to inspect it's contents, I find that the contents of these dirs have been dumped in the top level of the .jar.

Which looks like this:

.jar
    packages
    jar files
    fonts
    json files

So, when I attempt to load a config file with something like:

BufferedReader reader = new BufferedReader( new FileReader( path ) );

Everything works just file when I run the app in Eclipse. But the jar file throws a FileNotFoundException.

Many of the questions that I've seen on S.O. regarding problems like these recommend using using class.getClass().getResource() or class.getResourceAsStream(). I have tried both of these using relative paths and just the file name as in:

class.getResource( 'config.json' );
class.getResources( 'cfg/config.json' );
class.getResourceAsStream( '../../config.json' );

All of these methods return null, when run from either Eclipse or the jar using:

java -jar myjarfile.jar

I am also open to using an Ant file. In fact, I'm now using the Ant file generated by the export feature to build the jar. If there is something I can add to that to add the directories into the jar that would be great too.