code: public Reflections collect(final File file) {
          FileInputStream inputStream = null;
          try {
              inputStream = new FileInputStream(file);
              return collect(inputStream);
          } catch (FileNotFoundException e) {
              throw new ReflectionsException("could not obtain input stream from file " + file, e);
          } finally {
              Utils.close(inputStream);
          }
      }
docs: merges saved Reflections resources from the given file, using the serializer configured in this instance's Configuration
  <p> useful if you know the serialized resource location and prefer not to look it up the classpath