Using Scanner class with while and calling a menu which has four options

Question

I am learning java and want to make a small inventory management and which operates a menu in which there are 4 options:

1. View item
2. Sell Item
3. Place Order
4. Exit

I specifically want to do it with the help of while loop. I made the methods for the menu actions but when i call it in the while loop, it is not giving the desired result except when i press 1 to view product.

public class Item {

    private double cost,OrderPoint,AmountOnHand,PercentMarkup,OrderQuantity;
    private String NameOfItem, Supplier;


    Item(String NameOfItem,double cost,double PercentMarkup,String Supplier,double OrderQuantity,double OrderPoint,double AmountOnHand){
        this.NameOfItem=NameOfItem;
        this.cost=cost;
        this.PercentMarkup=PercentMarkup;
        this.Supplier=Supplier;
        this.OrderQuantity=OrderQuantity;
        this.OrderPoint=OrderPoint;
        this.AmountOnHand=AmountOnHand;

        }

    public String getNameOfItem()
     {
            return NameOfItem;
     }
    public String setNameOfItem()
     {
            return NameOfItem;
     }


    public double getCost()
     {
            return cost;
     }
    public double setCost()
     {
            return cost;
     }
    public String getSupplier()
     {
            return Supplier;
     }
    public String setSupplier()
     {
            return Supplier;
     }


    public double getOrderPoint()
     {
            return OrderPoint;
     }
    public double setOrderPoint()
     {
            return OrderPoint;
     }


    public double getAmountOnHand()
     {
            return AmountOnHand;
     }
     public double setAmountOnHand()
     {
            return AmountOnHand;
     }
    public double getPercentMarkup()
     {
            return PercentMarkup;
     }
     public double setPercentMarkup()
     {
            return PercentMarkup;
     }
    public double getOrderQuantity()
     {
            return OrderQuantity;
     }
     public double setOrderQuantity()
     {
            return OrderQuantity;
     }



public double PlaceOrder(){

    if(AmountOnHand<5) 
        AmountOnHand+=20;
    return AmountOnHand;


    }


public double SellItem() {
    if(AmountOnHand>0)
        AmountOnHand-=1;
    return AmountOnHand;


}



public String toString()
{
    String str="Name Of Item:" + this.getNameOfItem()+"\n";
    str=str+"Supplier:" +this.getSupplier()+"\n";
    str=str+"cost=" +this.cost+ "\n"; 
    str=str+"OrderPoint= " + this.OrderPoint+ "\n";
    str=str+"Amount On Hand= " +this.getAmountOnHand()+"\n";
    str=str+"PercentMarkup:"+this.getPercentMarkup()+"\n";
    str=str+"Order Quantity:" +this.getOrderQuantity()+"\n" ;
    return str;




    }

}

MAIN method:

public class ItemTest{      

    public static void main(String [] args) {
        Item product = new Item("Wrench",15,15%10+15,"Craftsmen Tool",20,5,4);
        System.out.println("Enter a Number");
        Scanner myScanner = new Scanner(System.in);
        int x=0;
        int choice = menu();
        while(choice !=4) {
            System.out.println("Enter a number");
            int aNumber= myScanner.nextInt();
            if (aNumber==1) {
            System.out.println("You entered"+product.toString());
            choice=menu();
            }
            else if (aNumber==2) {
                System.out.println("You entered 2"+product.SellItem());
                choice=menu();
                }
            else if (aNumber==3) {
                System.out.println("You entered 3"+product.PlaceOrder());
                choice=menu();
                }
            else
            {
                System.out.println("Thanks for Visiting");
            }
        }

    }

    private static int menu() {
        Scanner aScanner = new Scanner(System.in);

        int response=aScanner.nextInt();
        return response;
    }

}

Any help is appreciated. Thanks