LanyardJavaWrapper is, obviously, a Java wrapper for the Lanyard API, which you can find here.
Lanyard is a REST API that exposes Discord users' data within a seconds. In order to be monitored by Lanyard, you need to be in the Lanyard Discord Server. Once you've done that, you can start using your Discord info in your app as you please.
Currently, LanyardJavaWrapper is only available on Jitpack here. Eventually I'll transition away from it, but for now you can find everything you need there.
If you find any issues or bugs please report them!! You can also open a pull request to contribute your fix as long as it doesn't drastically change the functionality of the library.