Where is the data file on the android file system?

I can write a file to local storage of my (Samsung) tablet, with code like this:

String fileName = "myfile.ser";FileOutputStream fos = context.openFileOutput(fileName, Context.MODE_PRIVATE);ObjectOutputStream os = new ObjectOutputStream(fos);os.writeObject(this);os.close();

Reading is no problem either with similar code. I can see the file system in Windows explorer of the attached tablet via USB. But I cannot discover where on the Android file system the file "myfile.ser" is written?

Is it hidden?