The marc4j.jar file that is in `./lib` was created by:

Checking out the marc4j source from github.com/marc4j/marc4j, and building
with `ant` on 14 November 2013.

That produced the jar you see, with the name it has. (I am not sure the version
in the jar name is accurate as to matching any actual releases by other means)

It can be regenerated by doing the same.

Bundling the marc4j jar with our traject gem is not neccesarily the
best way to go, but it's what we're doing now, other ideas welcome.

(You can use your own custom marc4j.jar by using a runtime setting,
see docs. )