Welp
I tried it on a number of different PCs today, and it seems that the amount of memory it peaks at varies based on the system. Those with lower resources available peak lower; I'm wondering if this is some sort of built-in feature of Java caching the GUI and in which case there's probably nothing that can be done about it
Well, jConfig was a fairly small program - one of the first ones I did using swing components. For having like four buttons it can still consume upwards of 200,000K of RAM though if you drag the sides around enough.
There probably were some other problems but I haven't worked on it in like four days so I can't really remember D:
Maybe it will come to me soon