Please make these $3$ classes in java

The class should implement an invoice containing zero or more lines

$*$ of products with their prices and quantities, e$.$g$.,$

$*$ Oatmeal Cookies, price$=1\mathrm{.}99,$ quantity$=3$

$*($you may also think of it in terms of a "Shopping cart" $-$ to some extent the two are similar$).$

$*$

$*$ ONE public constructor should exist $($no other constructors are permitted$)$:

$*$ Invoice$()$: creates an empty invoice, so that the items can be added to it

$*$

$*$ In addition to the above, the following public methods should be implemented:

$*$

$*$ public void addItem$($Product item, int quantity$)-$ adds the new line to the invoice

$*$ NOTE: for simplicity, if the same items are added multiple times, they should remain on

$*$ separate lines $($i$.$e$.,$ identical products should NOT be merged into one line$)$

$*$

$*$ public List getItems$()-$ returns a list of all the invoice items,

$*$ with the items in the same order that they were added in using the addItem method above

$*$ IMPORTANT

$*$ The client calling getItems$()$ should not be able to change the invoice items

$*$

$*$ public double getTotal$()-$ returns the total cost of the items on the invoice

$*$

$*$ String toString$()$

$*$ this one should return a String in the following form:

$*$ Invoice

$*$ Chocolate Cake, price$=21\mathrm{.}99,$ quantity$=1$

$*$ Oatmeal Cookies, price$=1\mathrm{.}99,$ quantity$=3$

$*$ Tasty Chocolates, price$=0\mathrm{.}98,$ quantity$=30$

$*$ Total: $57\mathrm{.}36$

$*$

$*$ Of course, the numbers above may be very different for any particular instance

$*$

The class should implement an item describing a line on an invoice:

$*$ a product $($including its name and price$),$ and the quantity, as an integer

$*$ The quantity above can be any integer $($e$.$g$.,$ negative values indicate a product

$*$ return for a refund$)$

$*$

$*$ The class is intended to be used in the implementation of another class or classes

$*$

$*$ ONE public constructor should exist:

$*$ InvoiceItem$($Product product, int quantity$)$: creates an invoice line item with

$*$ the specified product and quantity

$*($you may add other $-$ non$-$public $-$ constructors, if you desire$)$

$*$

$*$ IMPORTANT

$*$ The product price may change after it's added to the invoice; however the price on the invoice

$*$ should not be affected $($e$.$g$.,$ if product that sells for $$2\mathrm{.}00$ is added to the invoice,

$*$ and then its price goes up to $$2\mathrm{.}50,$ the price of the items already added should remain $$2\mathrm{.}00.$

$*$ However, if more items are added they will use the new price of $$2\mathrm{.}50$

$*$

$*$ In addition, the following public methods should be implemented:

$*$ public Product getProduct$()$

$*$ public int getQuantity$()$

$*$ public void setQuantity$($int quantity$)$

$*$

$*$ String toString$()$

$*$ this one should return a String in the form of "name, price$=$X$,$ quantity$=$Y$"$

$*$ where X is the item price, with two decimal digits; and Y is the quantity

$*$The class should implement a product that could be sold in a store

$*$ The class is intended to be used in the implementation of another class or classes

$*$

$*$ ONE public constructor should exist:

$*$ Product$($String name, double price$)$: creates a product with the specified name and price

$*($you may add other $-$ non$-$public $-$ constructors, if you desire$)$

$*$

$*$ in addition to the above, the following public methods should be implemented:

$*$ public String getName$()$

$*$ public double getPrice$()$

$*$ public void setPrice$($double price$)$

$*$

$*$ String toString$()$

$*$ this one should return a String in the form of "name, price$=$X$"$ where X is the item price, with two decimal digits $($no quotation marks$)$