> I'd still argue that stdin/stdout/stderr are instances of IO streams. I'd hope all programmers are relatively confident with manipulating IO streams. But these particular instances are really familiar to people working in Unix and uncommon to Windows people.

So, if I reframed the question as "copy the contents of one file to another" and asked them to write a class that implements:

    public void copy(java.io.InputStream in, java.io.PrintStream out);

Would that change the solution?