code: @Deprecated
      public void validate() {
          if (fs == null) {
              throw new MongoException("no fs");
          }
          if (md5 == null) {
              throw new MongoException("no md5 stored");
          }
  
          DBObject cmd = new BasicDBObject("filemd5", id);
          cmd.put("root", fs.getBucketName());
          DBObject res = fs.getDB().command(cmd);
          if (res != null && res.containsField("md5")) {
              String m = res.get("md5").toString();
              if (m.equals(md5)) {
                  return;
              }
              throw new MongoException("md5 differ.  mine [" + md5 + "] theirs [" + m + "]");
          }
  
          // no md5 from the server
          throw new MongoException("no md5 returned from server: " + res);
  
      }
docs: Verifies that the MD5 matches between the database and the local file. This should be called after transferring a file.
  
  @throws MongoException if there's a failure
  @deprecated there is no replacement for this method