When 1.7.2 came out, they added a check that wouldn't allow you to call the method a in EntityTypes if there's already an entry with the same ID,...
to create an inventory use Bukkit.createInventory(InventoryHolder holder, int size, String title); Returns Inventory. the size of the inventory...
ProjectileHitEvent.getEntity().getShooter()
How does a String convert into a Player array? They're two completely different datatypes.
Separate names with a comma.