Cannot resolve symbol 'IOUtils'

I have used the following code to create a temporary file in my android app: ``` public File streamToFile (InputStream in) throws IOException { File tempFile = File.createTempFile("sample", ".tmp"); tempFile.deleteOnExit(); FileOutputStream out = new FileOutputStream(tempFile); IOUtils.copy(in, out); return tempFile; } ``` Now the problem is `Cannot resolve symbol 'IOUtils'`. I did a little bit of googling and discovered that for using IOUtils I need to download and include a jar file. I downloaded the jar file from here(commons-io-2.4-bin.zip). I added the jar named `commons-io-2.4.jar` from the zip to my bundle and when I tried to import it using: ``` import org.apache.commons.io.IOUtils; ``` It is showing error `Cannot resolve symbol 'io'`. So I tried to import it like: ``` import org.apache.commons.* ``` But still I am getting the error `Cannot resolve symbol 'IOUtils'`. Question 1 : Why am I getting this error? How to resolve it? Question 2 : Is there any way to create a temp file from an InputStream without using an external library? Or is this the most efficient way to do that? I am using android studio.