code in try / catch blocks not executing

Question

I'm a beginner java programmer, and I'm following Oracle's Java Tutorials.

On the page on Data Streams, using the example from the page (below), I can't get the code to execute.

Update File

import java.io.*;

public class DataStreams {
    static final String dataFile = "F://Java//DataStreams//invoicedata.txt"; // used to be non-existent file

    static final double[] prices = { 19.99, 9.99, 15.99, 3.99, 4.99 };
    static final int[] units = { 12, 8, 13, 29, 50 };
    static final String[] descs = {
        "Java T-shirt",
        "Java Mug",
        "Duke Juggling Dolls",
        "Java Pin",
        "Java Key Chain"
    };
    public static void main(String args[]) {
        try {
            DataOutputStream out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(dataFile)));

            for (int i = 0; i < prices.length; i ++) {
                out.writeDouble(prices[i]);
                out.writeInt(units[i]);
                out.writeUTF(descs[i]);
            }

            out.close(); // this was my mistake - didn't have this before

        } catch(IOException e){
            e.printStackTrace(); // used to be System.err.println();
        }

        double price;
        int unit;
        String desc;
        double total = 0.0;

        try {
            DataInputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream(dataFile)));

            while (true) {
                price = in.readDouble();
                unit = in.readInt();
                desc = in.readUTF();
                System.out.format("You ordered %d" + " units of %s at $%.2f%n",
                    unit, desc, price);
                total += unit * price;
            }
        } catch(IOException e) {
            e.printStackTrace(); // Used to be System.err.println();
        }

        System.out.format("Your total is %f.%n" , total);
    }
}

The code in the try and catch blocks are not executing, for some reason.

It compiles normally, but when I run it, the output is only:

Your total is 0.000000.

It doesn't write the data into the other file, which stays empty, and it doesn't write the prices, units, and descriptions.

It also doesn't write an error message.

What is wrong with my code??

Any answers would be greatly appreciated.

EDIT

not using out.close() after using the out was my mistake. Thanks for the answers!

Instead of System.err.println(); do e.printStackTrace(); to see the error messages... — jlordo
– jlordo, Commented Aug 26, 2013 at 18:33

Luca Basso Ricci · Accepted Answer · 2013-08-26 18:42:05Z

3

You have to close stream after use using out.close() to force flush before reusing it with in variable.

EDIT: (copied from my comment)
The file is created when you close it due to buffering caused by BufferedInputStream

edited Aug 26, 2013 at 18:42

answered Aug 26, 2013 at 18:33

Luca Basso Ricci

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1 Comment

Jonathan Lam Over a year ago

thanks @bellabax - that was the mistake. plus the fact that the file was nonexistent (silly me!)

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