code: @SuppressWarnings("unchecked")
      public KieContainerResource getContainer(String serverUrl, String container) {
  
          // in case of container is not instantiated the response doesn't parse ServiceResponse
          String response = client.target(serverUrl)
              .path("containers")
              .path(container)
              .request(MediaType.APPLICATION_JSON)
              .get(String.class);
          
          ServiceResponse<KieContainerResource> result = jsonMarshaller.unmarshall(response, ServiceResponse.class);
          return result.getResult();
  
      }
docs: Verify the container status on remote process server.
  
  @param serverUrl     remote process server URL
  @param container     container id
  @return KieContainerResource with status or null if the container in not instantiated