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.write("Hello World");
    myWriter.close();
    try (FileReader myReader = new FileReader("filename.txt")) {
      myReader.mark(100);
    } catch (IOException e) {
      System.out.println("FileReader does not support mark().");
    }
  }
}