I prefer the first style, GLFWCursorPosCallback etc. Prefix and camel case.
I haven't been able to register for the forums using an outlook email account for days-- finally had to use a gmail account. In any case, I'm here to make a bug report.
Exception in thread "main" org.lwjgl.system.libffi.ClosureError: Callback failed because the closure instance has been garbage collected.
at org.lwjgl.glfw.GLFW.glfwPollEvents(Native Method)
...
This error occurs at random (after some time has passed) when I press keys after using glfwSetKeyCallback. It seems that something is getting garbage collected that shouldn't. Perhaps this is related to the new ClosureRegistry that attempts to do automatic GC of closures?
It's possible that this affects other callbacks that are GCed at improper times as well, but I haven't tested them.
Also, it doesn't seem to be possible to use the system property "org.lwjgl.system.libffi.ClosureRegistry" to disable the automatic GC. I'm not sure if you intended that to be possible, but for it to work I'd have to set the entry to null, which System.setProperty doesn't allow.
Update: Switched to the latest nightly build and this error still occurs.