code: public List<URI> getURIs() {
          List<URI> uris = new ArrayList<URI>();
  
          lock.lock();
          try {
              List<URI> result = new ArrayList<URI>(uriIndex.keySet());
              result.remove(null);
              return Collections.unmodifiableList(result);
          } finally {
              uris.addAll(uriIndex.keySet());
              lock.unlock();
          }
      }
docs: Get all URIs, which are associated with at least one cookie
  of this cookie store.