Reading and Writing Files I – Introduction to Programming

Two of the most often used classes for reading and writing files are FileInputStream and FileOutputStream.

When opening files you must use a try-catch block.

public class FileIO {
    public static void main(String[] args) {
        Scanner sc;
        PrintWriter pw;
        try {
            sc = new Scanner(new FileInputStream("in.txt"));
            pw = new PrintWriter(new FileOutputStream("out.txt"));
            String token;
            while (sc.hasNext()){
                token = sc.next();
                pw.println(token);
            }
        } catch (FileNotFoundException e) {
            System.out.println("File not found: " + e.toString());
            return;
        }

        sc.close(); 
        pw.close();
    }
}