http://iharder.net/jpushbullet2
This is a Public Domain Java library for interacting with the Pushbullet service. It supports both sending and receiving notifications. Thanks to shakethat at github for the insights from his library, which was made for an earlier set of Pushbullet APIs.
I have released this software into the Public Domain. That means you can do whatever you want with it. Really. You don't have to match it up with any other open source license—just use it. You can rename the files, move the Java packages, whatever you want. If your lawyers say you have to have a license, contact me, and I'll make a special release to you under whatever reasonable license you desire: MIT, BSD, GPL, whatever.