Awesome. Wish I knew Java, as I would help - I tried learning it once but it is way over my head. Used to program in Qbasic back in the day.
Not sure if you are doing the full image compare yet, but I had some suggestions for when/if you do add this feature. I've been using ECUedit's image compare and it works fine if your two ROMs are the same revision, but if you are comparing two different revisions, it lists a bunch of tables that it claims has different data, but only have different addresses between them.
So, a good map compare should have the capability of comparing the data by cross referencing the string name for each image and their respective locations in their own file, rather than comparing address to address. So, for example, it would look up, say, "injector flow scaling" on both images by looking up the proper address on image 1 for this table and the proper address (which could be different) on image 2 as well and then just comparing the values that are found in each of those locations.
This would be awesome feature for seeing what Subaru has changed in newer revisions and for comparing two tuner maps that are different revisions/years. Of course, there are going to be some revisions that add/remove tables from previous versions, so the map compare should list all tables that it can't find to compare.