At first I want say that this engine is very cool! In jMonkey (thanks to AppState, Controls and good documentation with examples, thanks http://jmonkeyengine.ru site to) in my code order more when unity3d or libgdx AppState is very cool feature. ) For a few weeks, doing my free time on weekends, I feel good progress in my knowledge, while I do not feel much difficulty in studying)
Although my level of programming is not high.
One question. In unity3d there is internal UnityEvents or can be used c# eventsystem. I search event for jMonkey. I found guava eventsystem and greenrobot eventbus. what do you use for events?
There is no jme equivelent to unity events. If you want user input we have the input manager. If you want more general callbacks its not difficult to make an event system yourself.
The way unity handles events is very abstracted and error prone. Its much better to implement these sort of things on a per object basis using appatates, controls or user data.
If you desperately want a system similar to unity the guava eventbus looked useable from a quick glance. I have personally never needed anything like this and strongly recommend you stick with strong typing and clearly defined interactions between systems that need to communicate. Your design will be better because of it.