Java Directory monitor for changes for sub directories

import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.LinkOption;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.StandardCopyOption;
import java.nio.file.StandardWatchEventKinds;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.HashMap;
import java.util.Map;

public class Main implements Runnable {
   private final WatchService watcher = FileSystems.getDefault().newWatchService();
   private final Map<WatchKey, Path> keys = new HashMap<WatchKey, Path>();
   Path src, dst;//from  ww w . j  av a2s . c om

   Main(Path dir, Path dir1) throws IOException {
      src = dir;
      dst = dir1;
      register(dir);
   }

   private void register(Path dir) throws IOException {
      Files.walkFileTree(dir, new SimpleFileVisitor<Path>() {
         public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
            WatchKey key = dir.register(watcher, StandardWatchEventKinds.ENTRY_CREATE,
                  StandardWatchEventKinds.ENTRY_MODIFY);
            keys.put(key, dir);
            return FileVisitResult.CONTINUE;
         }
      });
      new Thread(this).start();
      System.out.println("Ready");
   }

   public void run() {
      while (true) {
         WatchKey key;
         try {
            key = watcher.take();
            System.out.println(key);
         } catch (InterruptedException x) {
            return;
         }

         Path dir = keys.get(key);
         if (dir == null) {
            System.err.println("WatchKey not recognized!!");
            continue;
         }

         for (WatchEvent<?> event : key.pollEvents()) {
            WatchEvent.Kind kind = event.kind();
            if (kind == StandardWatchEventKinds.OVERFLOW)
               continue;

            WatchEvent<Path> ev = (WatchEvent<Path>) event;
            Path name = ev.context();
            Path child = dir.resolve(name);
            System.out.format("%s: %s\n", event.kind().name(), child);
            Path r = src.relativize(child);
            Path to = Paths.get(dst + "/" + r);// , from = Paths.get(src+"/"+r);
            try {
               Files.copy(child, to, StandardCopyOption.REPLACE_EXISTING);
            } catch (Exception e) {
               Path p1 = Paths.get(src.toString());
               Path p2 = Paths.get(dst.toString());
               for (int i = 0; i < r.getNameCount(); i++) {
                  p1 = p1.resolve(r.getName(i));
                  p2 = p2.resolve(r.getName(i));
                  try {
                     Files.copy(p1, p2, StandardCopyOption.REPLACE_EXISTING);
                  } catch (Exception e1) {
                     System.out.println("again" + e);
                  }
               }
            }

            if ((kind == StandardWatchEventKinds.ENTRY_CREATE) && Files.isDirectory(child, LinkOption.NOFOLLOW_LINKS)) {

               try {
                  register(child);
               } catch (IOException x) {
               }
            }
         }
         boolean valid = key.reset();
      }
   }

   public static void main(String[] args) throws Exception {
      new Main(Paths.get(args[0]), Paths.get(args[1]));
   }
}