So, first, as a heads up, do realize that fileName.getBytes() as you have there gets the bytes of the filename, not the file itself.

Second, reading inside the docs of FileReader:

The constructors of this class assume that the default character encoding and the default byte-buffer size are appropriate. To specify these values yourself, construct an InputStreamReader on a FileInputStream.

So, sounds like FileReader actually isn't the way to go. If we take the advice in the docs, then you should just change your code to have:

String fileName = getFileNameToReadFromUserInput();
FileInputStream is = new FileInputStream(fileName);
InputStreamReader isr = new InputStreamReader(is, getCorrectCharsetToApply());
BufferedReader buffReader = new BufferedReader(isr);

and not try to make a FileReader at all.