import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class Main {
  public static void main(String[] args) throws IOException {
    FileWriter myWriter = new FileWriter("filename.txt");
    myWriter.append("Hello").append(' ').append("World");
    myWriter.close();
    BufferedReader br = new BufferedReader(new FileReader("filename.txt"));
    System.out.println(br.readLine());
    br.close();
  }
}