I don't have a straight answer (and I don't think there's one either, this is controlled at OS-level (native), not at JVM-level) and I also don't really see the value of the answer (you still can't close the file programmatically once you found out which thread it is), but I think you don't know yet that the inability to delete is usually caused when the file is still open. This may happen when you do not explicitly call Closeable#close()
on the InputStream
, OutputStream
, Reader
or Writer
which is constructed around the File
in question.
Basic demo:
public static void main(String[] args) throws Exception {
File file = new File("c:/test.txt"); // Precreate this test file first.
FileOutputStream output = new FileOutputStream(file); // This opens the file!
System.out.println(file.delete()); // false
output.close(); // This explicitly closes the file!
System.out.println(file.delete()); // true
}
In other words, ensure that throughout your entire Java IO stuff the code is properly closing the resources after use. The normal idiom is to do this in the finally
block, so that you can be certain that the resources will be freed up anyway, even in case of an IOException
. E.g.
OutputStream output = null;
try {
output = new FileOutputStream(file);
// ...
} finally {
if (output != null) try { output.close(); } catch (IOException logOrIgnore) {}
}
Do it for any InputStream
, OutputStream
, Reader
and Writer
which you're opening yourself (using the new
keyword).
This is technically not needed on certain implementations, such as ByteArrayOutputStream
, but for the sake of clarity, just adhere the close-in-finally idiom everywhere to avoid misconceptions and refactoring-bugs.
Hope this helps to nail down the root cause of your particular problem.