Method setTypeId

src/main/java/org/bukkit/inventory/ItemStack.java:93–96

Sets the type id of this item Note that in doing so you will reset the MaterialData for this stack @param type New type id to set the items in this stack to

(int type)

     * @param type New type id to set the items in this stack to
     */
    public void setTypeId(int type) {
        this.type = type;
        createData((byte) 0);
    }

    /**
     * Gets the amount of items in this stack