import java.io.FileInputStream;
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();
    FileInputStream input = new FileInputStream("filename.txt");
    System.out.println(input.available());
    input.read();
    System.out.println(input.available());
    input.close();
  }
}