code: public static TileSetBundle extractBundle (ResourceBundle bundle)
          throws IOException, ClassNotFoundException
      {
          // unserialize the tileset bundles array
          InputStream tbin = null;
          try {
              tbin = bundle.getResource(METADATA_PATH);
              ObjectInputStream oin = new ObjectInputStream(
                  new BufferedInputStream(tbin));
              TileSetBundle tsb = (TileSetBundle)oin.readObject();
              return tsb;
          } finally {
              StreamUtil.close(tbin);
          }
      }
docs: Extracts, but does not initialize, a serialized tileset bundle
  instance from the supplied resource bundle.