Hmm. Well, since a jar is really just a zip file and you have the zip calls available in java to extract its contents, one approach could be to just include the jar with your project as if its a raw resource (like any binary data file), then use the File io stuff (FileReader etc) to get a handle to it and read it in. I did this with a html file early on in my Android work. It worked, but I since found out I'd done it the hard way as the browser can access html files much easier than treating them as raw binaries.
Give me a prod if you're still struggling and I'll dig out that general data file loader I mentioned.