Java 7 - Verzeichnisse auf Änderungen überwachen mit dem WatchService

package de.tutorials.training;

import static java.nio.file.StandardWatchEventKind.ENTRY_CREATE;
import static java.nio.file.StandardWatchEventKind.ENTRY_DELETE;
import static java.nio.file.StandardWatchEventKind.ENTRY_MODIFY;

import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.nio.file.WatchEvent.Kind;

public class FileSystemWatcherExample {

	/**
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		WatchService watchService = FileSystems.getDefault().newWatchService();
		System.out.println(watchService);
		WatchKey watchKey = Paths.get("/tmp").register(watchService,new Kind<?>[] { ENTRY_CREATE, ENTRY_MODIFY, ENTRY_DELETE });

		while (true) {
			watchKey = watchService.take();

			for (WatchEvent<?> watchEvent : watchKey.pollEvents()) {
				System.out.println(watchEvent.kind() + " "
						+ ((Path) watchEvent.context()));
			}

			watchKey.reset();
		}
	}
}

ENTRY_CREATE test1.data
ENTRY_MODIFY test1.data

while(true) {
File f = new File("pfad");
if(f.exists()) {
doSomething();
}
try { Thread.sleep(500)  } catch (Exception ex) {};
}