static items in prinit is not static -.-
However methods like setUnlocalizedName, setRegistryName, etc.. follow a programming design called chaining.
Its when a method returns the object it's working on.
So you can do something like:
Item my_item = new MyItem().setUnlocalizeName().setRegistryName();
Side note, you shouldnt start your fields with upper case names, that's typically reserved for Class names.