public class ReadAndWriteIO {
    public void OpenFile ()
    {
    try {
        String line;
        BufferedReader in;
        BufferedWriter out;
        in = new BufferedReader(new FileReader("input.txt"));
        out = new BufferedWriter(new FileWriter("output.txt"));
            while ((line = in.readLine()) != null){
                System.out.println(line);
                out.write(line);
            }
            in.close();
            out.close();
        }
    catch(IOException e)
        {
            System.out.println("Tiedostoa ei löydy.");
        }
    }
}