Check if slot is empty

Hey i got this problem while trying to make a per slot whitelist plugin, where i want to get if a specific slot is empty. Can anybody help me with how to get if a slot is empty? This is my code so far

Code:java

@EventHandler
    public void onInventorypickupItem(InventoryPickupItemEvent e) {
        int item = e.getItem().getType().getTypeId();
        e.setCancelled(true);
        Player p = (Player)e.getInventory();
        for(int i = -1; i <= 35; i++) {
            String it = Integer.toString(i);
            if(fc.getBoolean(i + ".wl_true") == true) {
                for(String key : fc.getConfigurationSection(i + ".whitelist").getKeys(false)) {
                    int itemw = Integer.parseInt(key);
                    if(item == itemw && p.getInventory(). == i) {
                        p.getInventory().setItem(i, new ItemStack(item));
                        p.updateInventory();
                    }
                }
            }
        }
    }

I know that the code is broken, and full of errors, but i just got stuck at line 11.

 

AnAwesomeGuy
Do you mean the inventory slot?

Code:

if(p.getInventory().getItem(i) == null) {}

 

OMG, Im so stupid. I have been looking at this code for 3 hours and didn't see it . THANK YOU