NullPointer Exception

[john-paul York]

seems I make progress...need help..make some progress..and need more help....I am getting a nullPointerException for a project I am doing...I want to display all the info in each object that is in each order, so I got it to work if I fill the max number of items out, but if I don't fill the array it throws a nullPointer. I tried using a counter whenever a object was added and then during the display function just looping through with the max being that counter, but that did not seem to work. Any suggestions

 import javax.swing.*;  
 public class GadgetOrderTaker  
 {  
     private static int custID = 100;  
     private static String inputName="";  
     private static String inputAddress="";  
     private static int orderInput;  
     private static int orderNum; 
 

     
     public static void main (String[] args){  
      
     Gadget[] item = new Gadget[5];  
     item[0] = new Gadget(101, "Electic hand warmer", 12.99);  
     item[1] = new Gadget(124, "Batter-operated plant waterer", 7.55);  
     item[2] = new Gadget(256, "Gerbil trimmer", 9.99);  
     item[3] = new Gadget(512, "Talking Bookmark", 6.89);
       
     Order[] order1 = new Order[4]; //create array of 4 order objects
     for(int j=0;j<=3;j++){  //loop to create 4 order
     custID = custID +1;   //maybe can be used for changing customer order ID later
  	 int qty=0;
     double tempFinalPrice = 0.00; 
     order1[j] =  new Order(custID);   
     for (int x = 0; x <= 3; x++)  //loop to fill the 4 objects with user input
     {  
    
     orderInput = Integer.parseInt(JOptionPane.showInputDialog(null, "Which item would you like to order?\n"  
                 + "101 - Electric hand warmer - $12.99\n" + "124 - Battery operated plant warmer - 7.55\n"  
                 + "256 - Gerbil trimmer - 9.99\n" + "512 - Talking bookmark - 6.89\n" + "Enter item number only.")); 
     if(orderInput==101)  //this if statment is used to choose which gadget object to put in the order array
     	{
     	order1[j].items[x][0] = item[0];
     	
     	} 
     
     else if(orderInput==124)
     	{
     	order1[j].items[x][0] = item[1];
     		
     	} 
     	
     else if(orderInput==256)
     	{
     	order1[j].items[x][0] = item[2];
     			
     	} 
     	
     else if(orderInput==512)
     	{
     	order1[j].items[x][0] = item[3];
     		
     	} 
     
     else if (orderInput==999)  
             {
             	
                 JOptionPane.showMessageDialog(null,"Ending order");  
                 break;  
             }                    
       
     qty=Integer.parseInt(JOptionPane.showInputDialog(null,"Who many would you like?"));  //creates a Integer object for qty to go in 2 dimensional array in the order object
     Integer intObj1 = new Integer(qty);  
     order1[j].items[x][1] = intObj1;     
       
     tempFinalPrice+=((Gadget)order1[j].items[x][0]).getPrice()*((Integer)order1[j].items[x][1]);
     order1[j].setTotalPrice(tempFinalPrice);
 
     
    	 } 

     }             

        for(int q = 0; q<=3; q++)
        {
  	       	
        	String gadgetInfo="";
        	for (int u = 0; u<=3; u++)  // This for loop throws the exception if I don't have 4 items
        	{
        		gadgetInfo=gadgetInfo + ((Gadget)order1[q].items[u][0]).getItem() +" " + ((Gadget)order1[q].items[u][0]).getDesc() + " " + ((Gadget)order1[q].items[u][0]).getPrice();
        	}
 
        JOptionPane.showMessageDialog(null,"Order ID: " + order1[q].getOrderID() + "\n" + "Customers Name: " + order1[q].getCustName() + "\n" +
        							  "Customer Address: " + order1[q].getCustAddress() + "\n" + gadgetInfo );
        							  	
        }
 		
 		
     }  
       
 } 

[Campbell Ritchie]

If you create an array and don't fill it, that array will be full of null references. If you try to use those null references, you are liable to suffer a NullPointerException. So you want to fill any arrays as soon as possible after creation.