[Demonstration 1]

[Buggy Method]
public boolean hasOwnCard(EntityPlayer player) {
    for (int i = player.inventory.getSizeInventory() - 1; i >= 0; --i) {
        ItemStack stack = player.inventory.getStackInSlot(i);
        if (stack != null) {
            if (stack.getItem() == CoreItems.debitCardNew) {
                if (player.getDisplayName().equals(stack.stackTagCompound.getString("playerName"))) {
                    return true;
                }
            }
        }
    }
    return false;
}

[Buggy Hunk]
if (player.getDisplayName().equals(stack.stackTagCompound.getString("playerName"))) {

[Patch]
if (player.getUniqueID().toString().equals(stack.stackTagCompound.getString("playerUUID"))) {

[Demonstration 2]

[Buggy Method]
public void updateTicker() {
    xPos++;
    if (xPos > scroll[0].length())
        xPos = 0;
    for (int n = 0; n < 9 * 6; n++) {
        super.putStackInSlot(n, null);
    }
    for (int y = 0; y < 5; y++) {
        for (int x = 0; x < 9; x++) {
            String rowString = scroll[y];
            if (xPos + x < rowString.length() && rowString.charAt(xPos + x) == '1')
                super.putStackInSlot(x + (y * 9), new ItemStack(redstoneBlock));
            //else putStackInSlot(x + (y * 9), new ItemStack(slimeball));
        }
    }
}

[Buggy Hunk]
super.putStackInSlot(n, null);

[Patch]
super.putStackInSlot(n, ItemStack.NULL_STACK);

[Demonstration 3]

[Buggy Method]
@Override
public boolean isItemValidForSlot(int index, ItemStack stack) {
    if (stack != null && stack.getItem() instanceof ItemAttachment) {
        ItemAttachment item = (ItemAttachment) stack.getItem();
        Item inv = invStack.getItem();
        switch(item.getType()) {
            case SCOPE:
                return inv instanceof Scopeable;
            case HOLO_SCOPE:
                return inv instanceof HoloScopeable;
            case FLASH:
                return inv instanceof Flashable;
            case LASER:
                return inv instanceof Laserable;
            case SILENCER:
                return inv instanceof Silenceable;
        }
    }
    return false;
}

[Buggy Hunk]
if (stack != null && stack.getItem() instanceof ItemAttachment)

[Patch]
if (stack.getItem() instanceof ItemAttachment)