Android: Getting lastModified of a private file

I am trying to get the last modified date of an internal file and it always returns m开发者_运维百科e 0 although I could read the file properly. Can you please let me know if I am doing anything wrong...

Creating a file...

FileOutputStream Os = activity.openFileOutput("file1.jpg", Context.MODE_PRIVATE);

cachedImage.compress(CompressFormat.JPEG, 75, Os);

Os.close();

Reading the file...

long mod_time = 0;

File file = new File("file1".jpg");

mod_time = file.lastModified();

FileInputStream Is = activity.openFileInput("file1.jpg");

cachedImage = BitmapFactory.decodeStream(Is);

Is.close();

mod_time is always zero!!!!

Should be

File file = new File(activity.getFilesDir().getAbsolutePath() + "/file1.jpg");

That's where the file is created.
Simple check:

File file = new File("file1.jpg");
Log.e("x", file.getAbsolutePath());
// /file1.jpg
Log.e("x", "" + file.exists());
// false