If this were a static c library, or a cocoa framework I'd know what to do! But I don't know how to package a 3rd party jar library along with my own jar.

I've put the jar files in a new folder, added that folder to the PATH and CLASSPATH, and added that to the build path as an external library. I've added a user defined library in Eclipse ...

Newer versions of Java now require all JAR files to be signed with a valid code-signing key, and starting with Java 7 Update 51, unsigned or self-signed applications are blocked from running.