Please Help! I need to change this from a paperclip logo to a book logo

[keekee]

My code runs fine, but I keep getting this error message: I would like to change this logo from a paperclip logo to a book logo, my code is under the error. Can you tell me what's wrong and how to change it to a book logo?
Uncaught error fetching image:

java.lang.NullPointerException
        at sun.awt.image.URLImageSource.getConnection(URLImageSource.java:99)
        at sun.awt.image.URLImageSource.getDecoder(URLImageSource.java:113)
        at sun.awt.image.InputStreamImageSource.doFetch(InputStreamImageSource.j
ava:240)
        at sun.awt.image.ImageFetcher.fetchloop(ImageFetcher.java:172)
        at sun.awt.image.ImageFetcher.run(ImageFetcher.java:136)

code:

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.FlowLayout;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.Dimension;
import java.net.URL;


class Inventory {

    String number; // item number
    String name; // item name
    int quantity; // quanity of item
    double price; // item price

    public Inventory(String Number, String Name,  int Quantity, double Price)
    {
        number = Number;
        name = Name;
        quantity = Quantity;
        price = Price;
    }
    //Method set & get product name
    public void setName(String Name)
    {
        name = Name;
    }
    public String getName()
    {
        return name;
    }

    //Method set & get product number
    public void setNumber(String Number)
    {
        number = Number;
    }
    public String getNumber()
    {
        return number;
    }


    //Method set & get quantity of product
    public void setQuantity(int Quantity)
    {
        quantity = Quantity;
    }
    public int getQuantity()
    {
        return quantity;
    }


    //Method set & get product price
    public void setPrice(double Price)
    {
        price = Price;
    }
    public double getPrice()
    {
        return price;
    }

    //Method calculate inventory value
    public double getInventoryValue()
    {
        return price * quantity;
    }


    public String toString()
    {
        return "Item Name: "+name + "\nItem Number: "+number+"\nItem Price: $"+price+"\nQuantity in Stock: "+quantity + "\nInventory Value: $"+getInventoryValue();
    }
} // end Inventory Class



class Product extends Inventory {

    String brand;   // Subclass to add type of book
    double restockFee;  // Restock fee added to the inventory value

    // constructor initializes inventory information
    public Product(String brand, double restockFee, String Number, String Name,  int Quantity,  double Price)
    {
        super(Number, Name, Quantity, Price);
        this.brand = brand;
        this.restockFee = restockFee;
    }

    public Product(String brand, String Number, String Name,  int Quantity, double Price)
    {
        super(Number, Name, Quantity, Price);
        this.brand = brand;
        // default 5% restocking fee
        this.restockFee = 0.05;
    }

    public void setBrandName(String brand)
    {
        brand = brand;
    }
    public String getBrandName()
    {
        return brand;
    }


    public double getRestockFee() // Figures out restocking fee
    {
        return super.getInventoryValue() * restockFee;
    }

    public double getInventoryValue() // Total inventory value plus restocking fee
    {
        return  super.getInventoryValue() + (super.getInventoryValue() * restockFee);
    }

    public String toString()
    {
        StringBuffer sb = new StringBuffer ("\nBrand: ").append(brand).append("\n");
        sb.append (super.toString());


        return sb.toString();
    }

} // End Product Class


class Inventory2
{

    // store book inventory
    Product[] inventory;

    // store number of books added to inventory
    int number_of_products_in_inventory = 0;

    // create an inventory capable of holding maximum_number_of_products different products
    public Inventory2(int maximum_number_of_products)
    {
        inventory = new Product[maximum_number_of_products];
    }

    // add the books to the end of the inventory
    public void addProduct(Product products_to_add_to_inventory)
    {
        inventory[number_of_products_in_inventory] = products_to_add_to_inventory;
        number_of_products_in_inventory++;
    }
    // return the number of products in the inventory
    public Product getProduct(int index)
    {
        return inventory[index];
    }

    // return number of products in inventory
    public int getSize()
    {
        return number_of_products_in_inventory;
    }

    // run through all the books in the inventory, and add up their value.
    // this includes the restocking fee
    public double getTotalValueOfAllInventory()
    {
        double tot = 0.00;

        for(int i = 0; i < number_of_products_in_inventory; i++)
        {
            tot += inventory[i].getInventoryValue();
        }
        return tot;
    }

    // sort the books in the inventory by name
    public void sortInventory2()
    {
        // Sorting Inventory Information
        for(int j = 0; j < number_of_products_in_inventory - 1; j++)
        {
            for(int k = 0; k < number_of_products_in_inventory - 1; k++)
            {
                if(inventory[k].getName().compareToIgnoreCase(inventory[k+1].getName()) > 0)
                {
                    Product temp = inventory[k];
                    inventory[k] = inventory[k+1];
                    inventory[k+1] = temp;
                }
            }
        }
    }
} // End Inventory2 class

public class Inventory5 extends JFrame
{

    //create inventory for the books
    Inventory2 ProductInventory2;

    // index in the supply inventory of the currently displayed books. starts at 0, goes to the number of books in the inventory - 1
    int index = 0;


    // GUI elements to display currently selected books information
    private final JLabel nameLabel = new JLabel(" Product Name: ");
    private JTextField nameText;

    private final JLabel numberLabel = new JLabel(" Product Number: ");
    private JTextField numberText;

    private final JLabel brandLabel = new JLabel(" Brand: ");
    private JTextField brandText;

    private final JLabel priceLabel = new JLabel(" Price: ");
    private JTextField priceText;

    private final JLabel quantityLabel = new JLabel(" Quantity: ");
    private JTextField quantityText;

    private final JLabel valueLabel = new JLabel(" Value: ");
    private JTextField valueText;

    private final JLabel restockFeeLabel = new JLabel(" Restocking Fee: ");
    private JTextField restockFeeText;

    private final JLabel totalValueLabel = new JLabel(" Inventory Total: ");
    private JLabel totalValueText;


    // go to the next item in the list
    private Action nextAction  = new AbstractAction("Next") {
        public void actionPerformed(ActionEvent evt) {

        // check to see if there is a next book
        if (index == ProductInventory2.getSize() - 1) {
            // if we're at the book in the list, then we can't go any further
            // go to front of list
            index = 0;
        } else {
            index++;
        }

        repaint();
        }
    };
    private JButton nextButton = new JButton(nextAction);

    // go to previous book in the list
    private Action previousAction  = new AbstractAction("Previous") {
        public void actionPerformed(ActionEvent evt) {

        // if we're at the first book, then go to the last book in the list
        if (index == 0) {
            index = ProductInventory2.getSize() - 1;
        } else {
            index--;
        }

        repaint();
        }
    };
    private JButton previousButton = new JButton(previousAction);

    // go to the first book in list
    private Action firstAction  = new AbstractAction("First") {
        public void actionPerformed(ActionEvent evt) {

        index = 0;

        repaint();
        }
    };
    private JButton firstButton = new JButton(firstAction);

    // go to the last book in list
    private Action lastAction  = new AbstractAction("Last") {
        public void actionPerformed(ActionEvent evt) {

        index = ProductInventory2.getSize() - 1;

        repaint();
        }
    };
    private JButton lastButton = new JButton(lastAction);


    public void addProductToInventory2(Product temp)
    {
        ProductInventory2.addProduct(temp);
        repaint();
    }
    public void sortProductInventory2()
    {
        ProductInventory2.sortInventory2();
        repaint();
    }

    public Inventory5(int maximum_number_of_products)
    {
        // create the inventory object that will hold the book information
        ProductInventory2 = new Inventory2(maximum_number_of_products);

        // setup the GUI
        // add the next book button to the top of the GUI
        // setup panel to collect buttons in FlowLayout
        JPanel buttonPanel = new JPanel();
        buttonPanel.add(firstButton);
        buttonPanel.add(previousButton);
        buttonPanel.add(nextButton);
        buttonPanel.add(lastButton);
        getContentPane().add(buttonPanel, BorderLayout.NORTH);


        // setup logo for GUI
        URL url = this.getClass().getResource("logo.jpg");
           Image img = Toolkit.getDefaultToolkit().getImage(url);
        // scale image to fit in GUI
        Image scaledImage = img.getScaledInstance(205, 300, Image.SCALE_AREA_AVERAGING);
        // create JLabel with image as the label's Icon
        Icon logoIcon = new ImageIcon(scaledImage);
        JLabel companyLogoLabel = new JLabel(logoIcon);

        // add logo to GUI
        getContentPane().add(companyLogoLabel, BorderLayout.WEST);

        // book information
        // setup a panel to collect all the components.
        JPanel centerPanel = new JPanel(new GridLayout(8, 2, 0, 4));

        centerPanel.add(nameLabel);
        nameText = new JTextField("");
        nameText.setEditable(false);
        centerPanel.add(nameText);

        centerPanel.add(numberLabel);
        numberText = new JTextField("");
        numberText.setEditable(false);
        centerPanel.add(numberText);

        centerPanel.add(brandLabel);
        brandText = new JTextField("");
        brandText.setEditable(false);
        centerPanel.add(brandText);

        centerPanel.add(priceLabel);
        priceText = new JTextField("");
        priceText.setEditable(false);
        centerPanel.add(priceText);

        centerPanel.add(quantityLabel);
        quantityText = new JTextField("");
        quantityText.setEditable(false);
        centerPanel.add(quantityText);

        centerPanel.add(valueLabel);
        valueText = new JTextField("");
        valueText.setEditable(false);
        centerPanel.add(valueText);

        centerPanel.add(restockFeeLabel);
        restockFeeText = new JTextField("");
        restockFeeText.setEditable(false);
        centerPanel.add(restockFeeText);

        // add inventory information to panel
        centerPanel.add(totalValueLabel);
        totalValueText = new JLabel("");
        centerPanel.add(totalValueText);

        // add the panel to the center of the GUI's window
        getContentPane().add(centerPanel, BorderLayout.CENTER);

        repaint();
    }


    // repaint the GUI with new Product information
    public void repaint() {

        Product temp = ProductInventory2.getProduct(index);

        if (temp != null) {
            nameText.setText( temp.getName() );
            numberText.setText( ""+temp.getNumber() );
            brandText.setText( temp.getBrandName() );
            priceText.setText( String.format("$%.2f", temp.getPrice()) );
            quantityText.setText( ""+temp.getQuantity() );
            valueText.setText( String.format("$%.2f", temp.getPrice() * temp.getQuantity() ) );
            restockFeeText.setText( String.format("$%.2f", temp.getRestockFee() ) );
        }

        totalValueText.setText( String.format("$%.2f", ProductInventory2.getTotalValueOfAllInventory() ) );

    }


    public static void main(String args[])
    {

        // create new GUI object that will hold a maximum of 6 books
        Inventory5 Product_GUI = new Inventory5 (6);

        // Add the office supplies to the inventory
        Product_GUI.addProductToInventory2(new Product("HardBack", "1","Harry Potter" , 27, 15.99));
        Product_GUI.addProductToInventory2(new Product("HardBack", "2","Eragon" , 15, 10.99));
        Product_GUI.addProductToInventory2(new Product("SoftBack", "3","Letters to my Daughter", 14, 24.99));
        Product_GUI.addProductToInventory2(new Product("HardBack", "4","Twlight" , 20, 22.99));
        Product_GUI.addProductToInventory2(new Product("SoftBack", "5", "Eldest", 35, 11.99));
        Product_GUI.addProductToInventory2(new Product("SoftBack", "6", "The Da Vinci Code", 24, 9.00));


        // sort the books by name
        Product_GUI.sortProductInventory2();

        // Get GUI to show on screen
        Product_GUI.setDefaultCloseOperation( EXIT_ON_CLOSE );
        Product_GUI.pack();
        Product_GUI.setSize(700, 350);
        Product_GUI.setResizable(false);
        Product_GUI.setLocationRelativeTo( null );
        Product_GUI.setVisible(true);

        return;

    }
}  // End Inventory5 class

[masijade]

It probably means that the image you're trying to load doesn't exist. To change which image you're showing you need only change the image file you're loading, of course.