ItemStack

new ItemStack(int itemID, int amount)

Creates a new ItemStack object with the specified itemID and amount. itemID is an integer representing the ID of the item, and amount is the quantity of the item in the stack.

getAmount(): int

Returns the amount of items in this stack. This is an integer value representing the quantity of items.

getMaxAmount(): int

Retrieves the maximum amount of items allowed in this stack. This is an integer value representing the maximum stack size for this type of item.

getItemId(): int

Returns the item ID of the item in this stack. The item ID is an integer value that uniquely identifies the item type.

A list with all of the possible item ids can be found on this website.