Watch directory for modification in Java

import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;
/*ww w.  java 2 s. com*/
import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;

public class Main {
  public static void main(String[] args) throws Exception {
    WatchService watcher = FileSystems.getDefault().newWatchService();

    Path dir = FileSystems.getDefault().getPath("c:/");

    WatchKey key = dir.register(watcher, ENTRY_MODIFY);

    while (true) {
      key = watcher.take();
      for (WatchEvent<?> event : key.pollEvents()) {
        if (event.kind() == ENTRY_MODIFY) {
          System.out.println("Home dir changed!");
        }
      }
      key.reset();
    }
  }
}