How would I replenish a player's arrow when they shoot a bow?

I want a single arrow in a player's inventory to refresh every time it disappears. I tried using an EntityShootBowEvent, but it doesn't work and I don't know why.
Here's my code:

Code:

      public void skeletonShoot(EntityShootBowEvent shootEvent){
          ItemStack arrow = new ItemStack(Material.ARROW, 1);
          Player player = (Player) shootEvent.getEntity();
          Inventory inv = player.getInventory();

          inv.getContents();
          inv.setItem(1, arrow);
      }

Anyone have any ideas?

Edit: I just found a workaround solution to this by giving the player an arrow every time they click their bow with a PlayerInteractEvent. Thanks!

 

If you want to give them an arrow every time they shoot, why not just give their bows the infinity enchant? That'd be a lot easier.