Java coding issue

Question

I am doing a code for my "intro to java" programming course and I ran into an error I don't really know how to fix. I keep having an error that says:

unreported exception java.io.FileNotFoundException; must be caught or declared to be thrown
                Scanner fileIn = new Scanner(hours);

This is the code:

import java.util.Scanner;

import java.io.File;

public class program2{

    public static void main(String[] args)  { 

        int[][] array = new int [8][7];
        int[] total = new int [array.length];
        int[] finalTotal = new int[array.length];
        int[] employees = {0,1,2,3,4,5,6,7};


        File hours = new File("prog2.dat"); //read file
        Scanner fileIn = new Scanner(hours);//assign hours to array


        while(fileIn.hasNext()){
            for(int i = 0; i < 8; i++) {
                for (int a = 0; a < 7; a++) {
                    int num =fileIn.nextInt();
                        array[i][a] = num;
            }
        }
    }

    fileIn.close(); //Closes file

    // takes employees hour total
    for(int i=0; i < 8; i++) {
        total[i] = array[i][0] + array[i][1] + array[i][2] + 
        array[i][3] + array[i][4] + array[i][5] + array[i][6];
        }

    // takes the hours and sorts from greatest to least
    for(int i= 0; i < 7; i++) {
        int greatest = total[i];

        for(int b = i+1; b < 8; b++) {
            if(total[b] > greatest) {
                int employeeTemp = employees[i];
                employees[i] = employees[b];
                employees[b] = employeeTemp;
                int tempNum = greatest;
                greatest = total[b];
                total[i] = greatest;
                total[b] = tempNum;
            }
        }
    }

    // print employee number and worked hours
    for(int i = 0; i < 8; i++) {
        System.out.println(" Employee #" + employees[i] + ": " +
        total[i]);
        }

    }
}

Please help in any way you can.

haven't they told you at your "intro to java" programming course that using an IDE (like Eclipse at eclipse.org/downloads/index-developer.php ) helps? — EpicPandaForce
– EpicPandaForce, Commented Jul 15, 2014 at 11:43

Jigar Joshi · Accepted Answer · 2014-07-15 06:44:56Z

5

Scanner(fileInstance) declares to throw a FileNotFoundException so you must handle it

    Scanner fileIn = null;
    try{
       fileIn = new Scanner(hours)
    }catch(FileNotFoundException e){
        // write code that handles when this exceptional condition raises
    }

or rethrow it

public static void main(String[] args)  throws FileNotFoudnException {

Also See

Exceptions

edited Jul 15, 2014 at 6:44

answered Jul 15, 2014 at 6:43

Jigar Joshi

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3 Comments

JayT Over a year ago

When I do this, my compiler says it cannot find symbol: public static void main(String[] args) throws FileNotFoundException

Jigar Joshi Over a year ago

you need to import import java.io.FileNotFoundException;

EpicPandaForce Over a year ago

aka just press Shift+Ctrl+O in Eclipse

David Brossard · Accepted Answer · 2014-07-15 06:45:24Z

2

Change definition of your main method to:

public static void main(String[] args)  throws IOException {

Then read about exceptions in java to understand what does this mean.

edited Jul 15, 2014 at 6:45

David Brossard

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answered Jul 15, 2014 at 6:44

AlexR

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2 Comments

JayT Over a year ago

After doing this, my compiler is telling me that it cant find the symbol with IOException being the symbol

AlexR Over a year ago

Add import java.io.IOException; in the beginning of the file. And really, start learning java, not typing some text that looks like a code.

Mureinik · Accepted Answer · 2014-07-15 06:48:00Z

The call to Scanner fileIn = new Scanner(hours); may fail if the file is not found. In such a case, a java.io.FileNotFoundException will be thrown. Java is strict in its exception handling - you cannot just ignore this potential exception, but must handle it somehow.

One way of doing this is to add a throws clause to the main method:

public static void main(String[] args) throws FileNotFoundException {

In this case, the program will just crash if the file is not found. A better way, probably, to handle these kind of issues is to explicitly catch the exception:

Scanner fileIn = null;
try {
    File hours = new File("prog2.dat");
    fileIn = new Scanner(hours);
} catch (FileNotFoundException e) {
    System.out.println ("Can't find prog2.dat, quitting");
    System.exit(1);
}

Gaurav · Accepted Answer · 2014-07-15 06:48:41Z

0

Scanner fileIn = new Scanner(hours);//assign hours to array

This line of code throws an expection FileNotFoundException.

You have two option to solve this problem :

1) Catch the Exception

  Scanner fileIn = null;
        try {
            fileIn = new Scanner(hours);
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }//assign hours to array

2) Throw the Exception:

 public static void main(String[] args) throws FileNotFoundException  {

answered Jul 15, 2014 at 6:48

Gaurav

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Comments

premji · Accepted Answer · 2014-07-15 07:49:22Z

0

create prog2.dat file and also you enter some hours into that file.

Note: you must save prog2.dat into source directory

answered Jul 15, 2014 at 7:49

premji

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