import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) throws IOException {
    FileOutputStream output = new FileOutputStream("filename.txt");
    output.write("Hello World".getBytes());
    output.write('!');
    output.close();
    Scanner reader = new Scanner(new File("filename.txt"));
    System.out.println(reader.nextLine());
    reader.close();
  }
}