Java says FileNotFoundException but file exists

I have an assignment for my CS class where it says to read a file with several test scores and asks me to sum and average them. While summing and averaging is easy, I am having problems with the file reading. The instructor said to use this syntax

Scanner scores = new Scanner(new File("scores.dat"));

However, this throws a FileNotFoundException, but I have checked over and over again to see if the file exists in the current folder, and after that, I figured that it had to do something with the permissions. I changed the permissions for read and write for everyone, but it still did not work and it still keeps throwing the error. Does anyone have any idea why this may be occurring?

EDIT: It was actually pointing to a directory up, however, I have fixed that problem. Now file.exists() returns true, but when I try to put it in the Scanner, it throws the FileNotFoundException

Here is all my code

import java.util.Scanner;
import java.io.*;
public class readInt{
        public static void main(String args[]){
                File file = new File("lines.txt");
                System.out.println(file.exists());
                Scanner scan = new Scanner(file);
        }
}

There are a number situation where a FileNotFoundException may be thrown at runtime.

1. The named file does not exist. This could be for a number of reasons including:

   • The pathname is simply wrong
   • The pathname looks correct but is actually wrong because it contains non-printing characters (or homoglyphs) that you did not notice
   • The pathname is relative, and it doesn't resolve correctly relative to the actual current directory of the running application. This typically happens because the application's current directory is not what you are expecting or assuming.
   • The path to the file is is broken; e.g. a directory name of the path is incorrect, a symbolic link on the path is broken, or there is a permission problem with one of the path components.

2. The named file is actually a directory.

3. The named file cannot be opened for reading for some reason.

The good news that, the problem will inevitably be one of the above. It is just a matter of working out which. Here are some things that you can try:

• Calling file.exists() will tell you if any file system object exists with the given name / pathname.

• Calling file.isDirectory() will test if it is a directory.

• Calling file.canRead() will test if it is a readable file.

• This line will tell you what the current directory is:

    System.out.println(new File(".").getAbsolutePath());
  

• This line will print out the pathname in a way that makes it easier to spot things like unexpected leading or trailing whitespace:

    System.out.println("The path is '" + path + "'");
  

  Look for unexpected spaces, line breaks, etc in the output.

It turns out that your example code has a compilation error.

I ran your code without taking care of the complaint from Netbeans, only to get the following exception message:

Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - unreported exception java.io.FileNotFoundException; must be caught or declared to be thrown

If you change your code to the following, it will fix that problem.

public static void main(String[] args) throws FileNotFoundException {    
    File file = new File("scores.dat");
    System.out.println(file.exists());
    Scanner scan = new Scanner(file);
}

Explanation: the Scanner(File) constructor is declared as throwing the FileNotFoundException exception. (It happens the scanner it cannot open the file.) Now FileNotFoundException is a checked exception. That means that a method in which the exception may be thrown must either catch the exception or declare it in the throws clause. The above fix takes the latter approach.

The code itself is working correctly. The problem is, that the program working path is pointing to other place than you think.

Use this line and see where the path is:

System.out.println(new File(".").getAbsoluteFile());

Obviously there are a number of possible causes and the previous answers document them well, but here's how I solved this for in one particular case:

A student of mine had this problem and I nearly tore my hair out trying to figure it out. It turned out that the file didn't exist, even though it looked like it did. The problem was that Windows 7 was configured to "Hide file extensions for known file types." This means that if file appears to have the name "data.txt" its actual filename is "data.txt.txt".

Hope this helps others save themselves some hair.

I recently found interesting case that produces FileNotFoundExeption when file is obviously exists on the disk. In my program I read file path from another text file and create File object:

//String path was read from file
System.out.println(path); //file with exactly same visible path exists on disk
File file = new File(path); 
System.out.println(file.exists());  //false
System.out.println(file.canRead());  //false
FileInputStream fis = new FileInputStream(file);  // FileNotFoundExeption 

The cause of the problem was that the path contained invisible \r\n characters at the end.

The fix in my case was:

File file = new File(path.trim()); 

To generalize a bit, the invisible / non-printing characters could have include space or tab characters, and possibly others, and they could have appeared at the beginning of the path, at the end, or embedded in the path. Trim will work in some cases but not all. There are a couple of things that you can help to spot this kind of problem:

1. Output the pathname with quote characters around it; e.g.

     System.out.println("Check me! '" + path + "'");
   

   and carefully check the output for spaces and line breaks where they shouldn't be.

2. Use a Java debugger to carefully examine the pathname string, character by character, looking for characters that shouldn't be there. (Also check for homoglyph characters!)

An easy fix, which worked for me, is moving my files out of src and into the main folder of the project. It's not the best solution, but depending on the magnitude of the project and your time, it might be just perfect.