Question: I have the same jar file commons-io-2.4.jar both in the libs folder and in the Android Private Libraries. Is this a mistake? I got into this situation because I added the jar file to the Private Libraries and then I was told that it should be in the libs folder. I managed to put it in the libs folder, but I cannot delete it from the Private Libraries.

It looks like a method from this jar file does not work, because my application does not do anything after I call this method. And I don't get any error.

Answer: 
Putting a .jar file in your libs folder should cause it to automatically show up in the Android Private Libraries section, so that should be fine. What exactly is the method's expected behavior, and what is actually occurring?
I solved the problem, I need to put the input file in the sd card and to provide the right path.