So my code so far is this
 

public class MixingBowlBlockTileEntity extends LockableLootTileEntity {
 
    private NonNullList<ItemStack> bowlContents = NonNullList.withSize(12, ItemStack.EMPTY);
    PlayerEntity player;
 
    public MixingBowlBlockTileEntity(TileEntityType<?> tileEntityTypeIn) {
        super(tileEntityTypeIn);
    }
    
    
 
    public MixingBowlBlockTileEntity() {
        this(TileEntityTypesInit.MIXING_BOWL.get());
    }
 
    public CompoundNBT write(CompoundNBT compound) {
        super.write(compound);
        if (!this.checkLootAndWrite(compound)) {
            ItemStackHelper.saveAllItems(compound, this.bowlContents);
        }
 
        return compound;
    }
 
    public void read(BlockState state, CompoundNBT nbt) {
        super.read(state, nbt);
        this.bowlContents = NonNullList.withSize(this.getSizeInventory(), ItemStack.EMPTY);
        if (!this.checkLootAndRead(nbt)) {
            ItemStackHelper.loadAllItems(nbt, this.bowlContents);
        }
 
    }
 
    public int getSizeInventory() {
        return 12;
    }
 
    protected NonNullList<ItemStack> getItems() {
        return this.bowlContents;
        
    }
    
    
    
 
    protected void setItems(NonNullList<ItemStack> itemsIn) {
        this.bowlContents = itemsIn;
    }
 
 
 
 
 
    protected ITextComponent getDefaultName() {
        return new TranslationTextComponent("container.mixing_bowl");
    }
 
    @Override
    protected Container createMenu(int id, PlayerInventory player) {
        // TODO Auto-generated method stub
        return null;
    }
 
    @Override
    public int getInventoryStackLimit() {
        return 1;
    }
 
    public void addItemInventory(PlayerEntity playerIn, Hand handIn) {
        for (int i = 0; i < 9; i++) {
            if (!getStackInSlot(i).getItem().equals(Items.AIR)) {
                continue;
            }
            
            setInventorySlotContents(i, new ItemStack(playerIn.getHeldItemMainhand().getItem()));
            playerIn.getHeldItemMainhand().shrink(1);
            break;
 
        }
        
 
    }
    
    public void addLiquidInventory(PlayerEntity playerIn, Hand handIn) {
        for (int p = 9; p < 12; p++) {
            if (!getStackInSlot(p).getItem().equals(Items.AIR)) {
                continue;
            }
            setInventorySlotContents(p, new ItemStack(playerIn.getHeldItemMainhand().getItem()));
            int slot = playerIn.inventory.currentItem;
            playerIn.replaceItemInInventory(slot, new ItemStack(Items.BUCKET));
            System.out.println(bowlContents);
            break;
        }
    }
    
 
 
 
    public void removeLatestItem(PlayerEntity playerIn, World worldIn, BlockPos posIn, Hand handIn) {
        
        for(int e = 8; e > -1; e--){
            if(!getStackInSlot(e).getItem().equals(Items.AIR)) {
                if(playerIn.inventory.getFirstEmptyStack() != -1) {
                    playerIn.inventory.addItemStackToInventory(getStackInSlot(e).getStack());
                    setInventorySlotContents(e, new ItemStack (Items.AIR));
                    break;
                } else if(playerIn.inventory.hasItemStack(getStackInSlot(e).getStack())) {
                    playerIn.inventory.addItemStackToInventory(getStackInSlot(e).getStack());
                    setInventorySlotContents(e, new ItemStack (Items.AIR));
                    break;
                } else {
                    worldIn.addEntity(new ItemEntity(worldIn, posIn.getX() + 0.5, posIn.getY() + 1.125, posIn.getZ() + 0.5, getStackInSlot(e).getStack()));
                    setInventorySlotContents(e, new ItemStack (Items.AIR));
                    break;
                }
            }
            continue;
            
        }
 
        }
}

And it works fine but hoppers extract an item i dont want it to, I just want the hoopper not to extract a milk_bucket and water_bucket

Any help would be appriciated

Ok, how do i use the extractItem to only be able to extract a certain item then

Ive tried doing that but it isnt working, i could jsut be doing it wrong

private ItemStackHandler getHandler() {
        if (handler == null) {
            handler = new ItemStackHandler(1) {
                @Override
                public ItemStack extractItem(int slot, int amount, boolean simulate) {
                        if (getStackInSlot(1) == new ItemStack (Items.MILK_BUCKET)) {
                            return ItemStack.EMPTY;
                        }
                        
                    return super.extractItem(slot, amount, simulate);
                
            }
            
        };

    }
        return handler;
    }

Sorry i forgot that it starts at 0, not 1

dont create a new stack to check, check the item it self