This is invoked as part of initializing the GPLNativeCodeLoader class, and it would be awkward to try to pass a conf object. That's why I think a system property is a reasonable choice. Is that what you meant?

Also, are you talking about adding a unit test that exercises loading the native libraries from the jar? For what it's worth, all the current unit tests do exercise most of the code here that loads the native libraries from the "jar". Granted there is no jar during the unit tests, but it reads the native libraries using the classloader, copies it to the temp location, etc. Does that answer your question, or did you mean something else?