Simple download automatisation

Main.java

import java.io.IOException;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class Main {

  public static void main(String[] args) throws IOException {
    final ExecutorService executorService = Executors.newFixedThreadPool(10);
    for (int i = 0; i < 5001; i++) {
      executorService.submit(new DownloadAndSave(i));
    }
  }

}

class DownloadAndSave implements Runnable {
  private final int num;

  DownloadAndSave(int num) {
    this.num = num;
  }

  @Override
  public void run() {
    try {
      Files.copy(
          new URL(url()).openConnection().getInputStream(),
          Paths.get(filename()));
      System.out.println(num);
    } catch (IOException e) {
      System.out.println(num + " " + e.getMessage());
    }
  }

  String filename() {
    return "todo" + num;
  }

  String url() {
    return "http://example.org/?id=" + num;
  }
}