One of the things about JOpt Simple about which I feel most proud is the fact that I advertise alternatives to it on the project's website. I realize that choices abound for command line option parsing in Java; before you choose JOpt Simple, I'd like you to see the other choices and come back to JOpt Simple for its approachability, dedication to traditional Unix option syntaxes, and thorough tests.
I've decided to advertise alternatives to Property Binder on its site as well. In 2009, I took inspiration from a blog post to hammer out the beginnings of Property Binder for an article. Not long afterward (Aug 2009), I moved the project to GitHub; as of this writing, it sits at version 3.1. Since I started Property Binder, other alternatives have arisen.
If a facility for binding sources of Java application configuration to instances of an interface interests you, check out Property Binder's page and from there also check out the alternatives to Property Binder of which I'm aware. I hope you'll choose Property Binder!