Why this might happen:

1. The file is missing
   Even though the path is there, the actual file might not be in the correct place.

2. The path is wrong
   The program might be looking in a different folder than you expect. It might be using a relative path (like just myfile.txt), which depends on where the app runs from.

3. It's a file from resources, but used like a normal file
   If the file is inside src/main/resources, you can’t use new File("myfile.txt") directly. You need to load it like this:

   InputStream input = getClass().getResourceAsStream("/myfile.txt");