Please Help! Can someone tell me what this error means and how to fix it?

[keekee]

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)

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

[darkagn]

Somewhere in your code you are passing a null value when you can't. If I had to guess I would say your problem occurs somewhere near these lines of code:

URL url = this.getClass().getResource("logo.jpg");
Image img = Toolkit.getDefaultToolkit().getImage(url);

[masijade]

Correct, and, as I said in your other thread, it is because the image file (as referenced there) doesn't exist. Read the API docs for the getResource method carefully and completely.

[fred1702]

And if the image file could not exist, you should catch the java.lang.NullPointerException

try{
...
}
catch(java.lang.NullPointerException e)
{
...
}

[keekee]

Somewhere in your code you are passing a null value when you can't. If I had to guess I would say your problem occurs somewhere near these lines of code:

URL url = this.getClass().getResource("logo.jpg");
Image img = Toolkit.getDefaultToolkit().getImage(url);

Thank you for your help, but now I am getting this error that I do not understand.

java: 327: cannot find symbol
symbol: variable img
location: class inventory 5
image scaledImage = img.getScaledInstance(205, 300.SCALE_AREA_AVERAGING);

// setup logo for GUI
		ImageIcon ic = new ImageIcon("logo.jpg");
		   JLabel label = new JLabel(ic);
		// 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);

[masijade]

You defined your imageicon as ic and then try to use it as img.