Getting String from Java Class on Android

Alright, in my Android App I get a string from the user. Then, after a button click, I load up Unity. I need some way to get that string. (so basically I have the same question as http://answers.unity3d.com/questions/168707/accessing-data-from-a-android-java-class.html ).

To me, the documentation is not clear. I've made the jar file with my class, added to /plugins/android/blah.jar and then followed the documentation but I can get nothing to work (always a null string).

The documentation is just not clear to me... can anybody dumb it down or explain the process in more detail? (By no means do I want anything written for me but I've spent the past 4 hours on this and need some help)