How to tell why a file deletion fails in Java?

Question

File file = new File(path);
if (!file.delete())
{
    throw new IOException(
        \"Failed to delete the file because: \" +
        getReasonForFileDeletionFailur         


        

Answer 1

A deletion may fail due to one or more reasons:

1. File does not exist (use File#exists() to test).
2. File is locked (because it is opened by another app (or your own code!).
3. You are not authorized (but that would have thrown a SecurityException, not returned false!).

So whenever deletion fails, do a File#exists() to check if it is caused by 1) or 2).

Summarized:

if (!file.delete()) {
    String message = file.exists() ? "is in use by another app" : "does not exist";
    throw new IOException("Cannot delete file, because file " + message + ".");
}