code: public Reflections collect(final InputStream inputStream) {
          try {
              merge(configuration.getSerializer().read(inputStream));
              if (log != null) log.info("Reflections collected metadata from input stream using serializer " + configuration.getSerializer().getClass().getName());
          } catch (Exception ex) {
              throw new ReflectionsException("could not merge input stream", ex);
          }
  
          return this;
      }
docs: merges saved Reflections resources from the given input stream, using the serializer configured in this instance's Configuration
  <br> useful if you know the serialized resource location and prefer not to look it up the classpath