code: public void unsubscribeFromTopic() {
          try {
              HttpGet request = new HttpGet(unsubscribeUrl.toURI());
              HttpResponse response = httpClient.execute(request);
              if (!ApacheUtils.isRequestSuccessful(response)) {
                  throw new SdkClientException(String.format("Could not unsubscribe from %s: %d %s.%n%s",
                                                             getTopicArn(),
                                                             response.getStatusLine().getStatusCode(),
                                                             response.getStatusLine().getReasonPhrase(),
                                                             IOUtils.toString(response.getEntity().getContent())));
              }
          } catch (Exception e) {
              throw new SdkClientException(e);
          }
  
      }
docs: Unsubscribes this endpoint from the topic.