[java] Java says FileNotFoundException but file exists

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 trainiong 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.