Spawning "GREEN" Villager, new profession and event

Hi all, for my plugin i need to make a new profession for villager same as a NPC guard with event for fight and protect area.

First i don't know how to spawn a simple Villager without profession ("grren" villager) i used :

Code:

Entity e = w.spawnCreature(player.getLocation(), EntityType.VILLAGER);
 
Villager v = (Villager)e;
v.setProfession(Profession.getProfession(5));
or
v.setProfession(Profession.FARMER);

But when i used the first method, with "getProfession(id)" i got an error, can i make my own profession or not ?
If yes how ... i have test to implements Villager with a personnal class but nothing i don't know how to proceed.

Sorry for my english i'm french ..

EDIT :
I used : "
Entity e = w.spawnCreature(player.getLocation(), EntityType.VILLAGER);" because i modify some option like "Creature c = (Creature)e;" and "c.setTarget(player);"

 

In my plugin TransformCreature on BukkitDev, I set the profession by like:
v.setProfession(librarian) as opposed to an int