@Override
  public void nodeDeleted(String path) {
    if (!path.equals(pathToWatch)) {
      return;
    }
    if (LOG.isDebugEnabled()) {
      LOG.debug("Processing delete on {}", pathToWatch);
    }
    deletedLatch.countDown();
  }
Get the last exception which has occurred when re-setting the watch. Use hasException() to
check whether or not an exception has occurred.
@return The last exception observed when re-setting the watch.
hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/DeletionListener.java