Can't compile this

I'm trying to help my friend with this java crap cept I have no idea what's going on.

He thinks the problem lies within ShoppingCart.java but I will include everything.

ShoppingCart.java
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import java.io.*;
import java.util.*;

public class ShoppingCart
{

public static void main(String argv[])
{
// instantiates products to populate the catalog
GolfClub g1 = new GolfClub(59.99, 123456789, 25, "new", "Titleist", "driver");
GolfClub g2 = new GolfClub(69.99, 234567890, 50, "used", "Callaway", "putter");
GolfClub g3 = new GolfClub(79.99, 345678901, 75, "new", "Ping", "9 iron");
TennisBall t1 = new TennisBall(1.99, 987654321, 100, "new", "Penn", "green");
TennisBall t2 = new TennisBall(1.79, 876543210, 125, "new", "Wilson", "orange");
TennisBall t3 = new TennisBall(1.09, 765432109, 150, "used", "Gamma", "yellow");

int choice = 0;
Integer i = new Integer(0);
while(choice != 5) // choosing option 5 exits program
{

// display the menu
displayMenu();

// get input and put it into an Integer object...
try
{
i = new Integer(getString());
}
catch (NumberFormatException e1)
{
System.out.println ("ERROR - This is not a valid menu option!");
}
// ... so we can extract the int value from it
choice = i.intValue();

switch(choice)
{
case 1: // if user chooses option 1
displayCatalog(g1, g2, g3, t1, t2, t3);
break;

case 2: // if user chooses option 2
displayCart();
break;

case 3: // if user chooses option 3
addToCart();
break;

case 4: // if user chooses option 4
deleteFromCart();
break;

case 5: // if you choose 5
System.out.println("Thank you for using Crazy " +
"Larry's Shopping Cart.\n" +
"Did you hear that?\n" +
"Gotta go!\n");
break;

default: // if user chooses an invalid option
System.out.println("Invalid choice. Please try again.");
break;
}
}
}

public static String getString()
{
/**
* Retrieves a line of text from the keyboard
*
* @return A line of text from the keyboard as a String
*/

// initialize String to hold input
String returnString = "";

// creat input object
BufferedReader input = new BufferedReader(new InputStreamReader(System.in));

try
{
returnString = input.readLine();
}

catch(IOException e) {;}

return returnString;
}

public static void displayMenu()
{
System.out.println("New Menu");
System.out.println("1. Display products catalog");
System.out.println("2. Display items in cart");
System.out.println("3. Add an item to cart");
System.out.println("4. Delete an item from cart");
System.out.println("5. Exit/Checkout");
}

public static void displayCatalog(GolfClub g1, GolfClub g2, GolfClub g3, TennisBall t1, TennisBall t2, TennisBall t3)
/**
* Method for displaying the products in the catalog
*/
{
System.out.println("It# UPC Code Product Qty Price Brand Name Type/Color\n" +
" 1. " + g1.getUpc() + " golf club "+ g1.getQuantity() + " $" + g1.getPrice() + " " + g1.getBrandName() + " " +g1.getClubType() + "\n" +
" 2. " + g2.getUpc() + " golf club "+ g2.getQuantity() + " $" + g2.getPrice() + " " + g2.getBrandName() + " " +g2.getClubType() + "\n" +
" 3. " + g3.getUpc() + " golf club "+ g3.getQuantity() + " $" + g3.getPrice() + " " + g3.getBrandName() + " " +g3.getClubType() + "\n" +
" 4. " + t1.getUpc() + " tennis ball "+ t1.getQuantity() + " $" + t1.getPrice() + " " + t1.getBrandName() + " " +t1.getBallColor() + "\n" +
" 5. " + t2.getUpc() + " tennis ball "+ t2.getQuantity() + " $" + t2.getPrice() + " " + t2.getBrandName() + " " +t2.getBallColor() + "\n" +
" 6. " + t3.getUpc() + " tennis ball "+ t3.getQuantity() + " $" + t3.getPrice() + " " + t3.getBrandName() + " " +t3.getBallColor() + "\n");
}

public static void displayCart()
/**
* Method for displaying the items in the cart
*/
{

}

public static void addToCart()
/**
* Method for adding items to the cart
*/
{

}

public static void deleteFromCart()
/**
* Method for deleting items from the cart
*/
{

}
}
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GolfClub.java
-------------------------------------------------------
import java.util.*;

public class GolfClub extends SportingItem2 //indicates inheritance
{

// Additional attributes specific to a golf club
private String brandName;
private String clubType;

//Constructor for a new GolfClub object.
public GolfClub(double p, long u, int q, String n, String bn, String ct)
{
/* Price, UPC, quantity, and neworused are handled by the
* constructor for a SportingItem2 object, invoked with
* the following statement
*/
super(p, u, q, n);

// Attributes specific to a golf club
brandName = bn;
clubType = ct;
}

public String getBrandName()
{
return this.brandName;
}

public void setBrandName(String bn)
{
this.brandName = bn;
}

public String getClubType()
{
return this.clubType;
}

public void setClubType(String ct)
{
this.clubType = ct;
}

public String toString()
{
return "Golf Club Object:\n" +
"Price: " + this.getPrice() + "\n" +
"UPC: " +this.getUpc() + "\n" +
"Quantity: " + this.getQuantity() + "\n" +
"New or Used: " + this.getNeworused() + "\n" +
"Brand Name: " + this.brandName + "\n" +
"Club Type: " + this.clubType;
}

/**
* Method to create a deep copy of a GolfClub object
*/
public GolfClub golfClubCopy()
{
GolfClub gcopy = new GolfClub();

gcopy.price = this.price;
gcopy.upc = this.upc;
gcopy.quantity = this.quantity;
gcopy.neworused = this.neworused;
gcopy.brandName = this.brandName;
gcopy.clubType = this.clubType;

return gcopy;
}
}
-------------------------------------------------------

TennisBall.java
-------------------------------------------------------

import java.util.*;

public class TennisBall extends SportingItem2 //indicates inheritance
{

// Additional attributes specific to a tennis ball
private String brandName;
private String ballColor;

//Constructor for a new TennisBall object.
public TennisBall(double p, long u, int q, String n, String bn, String bc)
{
/* Price, UPC, quantity, and neworused are handled by the
* constructor for a SportingItem2 object, invoked with
* the following statement
*/
super(p, u, q, n);

// Attributes specific to a tennis ball
brandName = bn;
ballColor = bc;
}

public String getBrandName()
{
return this.brandName;
}

public void setBrandName(String bn)
{
this.brandName = bn;
}

public String getBallColor()
{
return this.ballColor;
}

public void setBallColor(String ct)
{
this.ballColor = ct;
}

public String toString()
{
return "Tennis Ball Object:\n" +
"Price: " + this.getPrice() + "\n" +
"UPC: " +this.getUpc() + "\n" +
"Quantity: " + this.getQuantity() + "\n" +
"New or Used: " + this.getNeworused() + "\n" +
"Brand Name: " + this.brandName + "\n" +
"Ball Color: " + this.ballColor;
}

/**
* Method to create a deep copy of a TennisBall object
*/
public TennisBall tennisBallCopy()
{
TennisBall tcopy = new TennisBall();

tcopy.price = this.price;
tcopy.upc = this.upc;
tcopy.quantity = this.quantity;
tcopy.neworused = this.neworused;
tcopy.brandName = this.brandName;
tcopy.ballColor = this.ballColor;

return tcopy;
}
}
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HELP!!!!!!!!!!!!!!