Array Index Out Of Bounds Exception

[Cary Tanner]

I'm getting and error when I try to run this program

package java146.project1;
 
import java.io.*;
import java.util.*;
 
/**
 *  Takes input from an input file and creates an array of OrderWithCharge
 *  objects. Then writes each object to an output file.
 *
 */
public class ProcessOrders extends Order {
 
    private List list1 = new ArrayList();
    Order[] orders;
 
 
    /**
     *  The main processing method for the ProcessOrders class.
     *
     *@exception  Exception  Description of the Exception
     */
    public void run() throws Exception {
        System.out.println("in the runApp method");
        readOrderFile();
        readChargesFile();
        createOrders();
        writeOutput();
 
    }
 
 
    /**
     *  Reads orderin.txt one line at a time, using a BufferedReader object, and
     *  adds the lines to an ArrayList object.
     *
     *@exception  Exception  Description of the Exception
     */
    public void readOrderFile() throws Exception {
        System.out.println("in the readOrder method");
 
        BufferedReader in = new BufferedReader(new FileReader("data/orderin.txt"));
 
        String line = "";
        while (in.ready()) {
            line = in.readLine();
 
            list1.add(line);
        }
 
        in.close();
 
    }
 
 
    /**
     *  Reads the charges file and loads infomation into two parallel arrays;
     *  one for rand limits, and one for handling charges.
     *
     *@exception  Exception  Description of the Exception
     */
    public void readChargesFile() throws Exception {
        System.out.println("in the readCharges method");
 
        BufferedReader in = new BufferedReader(new FileReader("data/charges.dat"));
 
        String[] parsedLine = null;
        String line = null;
        int[] quantityOrdered= new int[4];
        double[] handlingChargeAmount = new double[4];
        int i = 0;
 
        while (in.ready()) {
            line = in.readLine();
 
            parsedLine = line.split(" ");
            quantityOrdered[i] = Integer.parseInt(parsedLine[0]);
            handlingChargeAmount[i] = Double.parseDouble(parsedLine[0]);
            i += 1;
        }
 
        in.close();
 
        super.setQuantityOrdered(quantityOrdered);
        super.setHandlingChargeAmount(handlingChargeAmount);
 
    }
 
 
    /**
     *  Creates an array of OrderWithCharge objects with length equal to the
     *  size of the ArrayList object. Processes each string in the ArrayList
     *  object, spliting each line using the split() method, and passing the
     *  resulting fields to each OrderWithCharge object.
     *
     *@exception  Exception  Description of the Exception
     */
    public void createOrders() throws Exception {
        System.out.println("in the createOrders method");
 
        orders = new Order[list1.size()];
        Order o;
        String str = "";
        String[] pl = null;
        int i = 0;
        for (Iterator it = list1.iterator(); it.hasNext(); ) {
            str = (String) it.next();
            pl = str.split(" ");
 
            o = new Order();
            o.setCustName(pl[0]);
            o.setCustNum(Integer.parseInt(pl[1]));
            o.setQuantity(Integer.parseInt(pl[2]));
            o.setUnitPrice(Double.parseDouble(pl[3]));
            o.setItem(pl[4]);
            orders[i] = o;
            i += 1;
        }
 
    }
 
 
    /**
     *  Writes the order information to a file called orderout.txt, in the
     *  output directory.
     *
     *@exception  Exception  Description of the Exception
     */
    public void writeOutput() throws Exception {
        System.out.println("in the output method");
        PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("output/orderout.txt")));
        
        for (int i = 0; i < 5; i++) {
           out.println(orders[i]);
        }
 
        out.close();
 
    }
 
}

package java146.project1;
 
import java.io.*;
 
/**
 *  Driver class for Project 1
 *
 */
public class OrderDriver{
 
    /**
     *  The main program for the OrderDriver class
     *
     *@param  args           The command line arguments
     *@exception  Exception  Description of the Exception
     */
    public static void main(String[] args) throws Exception {
        System.out.println("in the driver method");
        ProcessOrders po = new ProcessOrders();
        po.run();
    }
 
}

Here's what I get:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4
at java146.project1.ProcessOrders.writeOutput(ProcessOrders.java:135)
at java146.project1.ProcessOrders.run(ProcessOrders.java:29)
at java146.project1.OrderDriver.main(OrderDriver.java:22)


I don't understand why this is happening.
[ February 08, 2005: Message edited by: Cary Tanner ]

[Steven Bell]

Your orders Array is only of size 4. Why the magic number 5 in the writeOutput for loop? It should be i < orders.length.

[Cary Tanner]

Silly me, that's what I did at first but I guess I wrote "i <= orders.length", and the equals is what screwed me up. Thanks!

[Ray Stojonic]

ArrayIndexOutOfBoundException indicates you have asked for an element of the array that doesn't exist.

If your array was:
int[] array = {1,2,3};
and you asked for array[3], you would get this exception. (remember, Java arrays are zero based, so array[3] would refer to the 4th element, if it existed)

That said, it is always better to use the length of the array to control a for when iterating through an array, as so:

for( int i = 0; i < array.length; ++i )

this way, you can't overrun the array because the array size itself is controlling the loop.

In your case, you need to fix line 135 in your program (as per the error message)