Java introp

[seyedjafariy]

Using the library from Java is a little hard.
With a couple of annotations, we can improve it much more.

I'll see if I can manage to send a PR for this

this is the current code we need in java:

        TowerObserver[] observers = {new WebWatchTowerObserver(8085, 5003)};
        WatchTower.INSTANCE.start(observers, 100);