code: private byte[] normalize(byte[] path) {
      if (path.length == 0)
        return path;
      byte prevC = 0;
      for (int i = 0; i < path.length; i++) {
        byte c = path[i];
        if (c == '\\')
          return normalize(path, i);
        if (c == (byte) '/' && prevC == '/')
          return normalize(path, i - 1);
        if (c == '\u0000')
          throw new InvalidPathException(this.hdfs.getString(path),
              "Path: nul character not allowed");
        prevC = c;
      }
      return path;
    }
docs: and check for invalid characters