Read XML File And Delete Its Contents - Boolean Doesn't Appear To Work

I'm trying to read a xml file and delete it's contents. I do this by reading the file,writing it to a temp and then overwriting the original with the temp by renaming it

//overwrite original xml file with new file
boolean successful = outputFile.renameTo(inputFile);
System.out.println("success");

It does say the value of the local variable is not used however. I've debugged to ensure it hits the code it always prints out the line after too.It just does not overwrite my original xml file with the temp one.

It's had votes on stack so I thought that would of been reputableStack - overwrite but the second one got voted as a good answer. But still I would like to know if my code can work or not.