code: public <T extends Item> List<T> getItems(List<ExtensionElement> additionalExtensions,
                      List<ExtensionElement> returnedExtensions) throws NoResponseException,
                      XMPPErrorException, NotConnectedException, InterruptedException {
          PubSub request = createPubsubPacket(Type.get, new GetItemsRequest(getId()));
          request.addExtensions(additionalExtensions);
          return getItems(request, returnedExtensions);
      }
docs: Get items persisted on the node.
  <p>
  {@code additionalExtensions} can be used e.g. to add a "Result Set Management" extension.
  {@code returnedExtensions} will be filled with the stanza extensions found in the answer.
  </p>
  
  @param additionalExtensions additional {@code PacketExtensions} to be added to the request.
  This is an optional argument, if provided as null no extensions will be added.
  @param returnedExtensions a collection that will be filled with the returned packet
  extensions. This is an optional argument, if provided as null it won't be populated.
  @param <T> type of the items.
  
  @return List of {@link Item}
  @throws NoResponseException
  @throws XMPPErrorException
  @throws NotConnectedException
  @throws InterruptedException