public ContainerHeartbeatResponse requestHeartbeat() {
    ObjectMapper mapper = new ObjectMapper();
    ContainerHeartbeatResponse response;
    String reply = "";
    try {
      reply = httpGet(new URL(heartbeatEndpoint));
      LOG.debug("Container Heartbeat got response {}", reply);
      response = mapper.readValue(reply, ContainerHeartbeatResponse.class);
      return response;
    } catch (Exception e) {
      LOG.error("Error in container heartbeat to JobCoordinator.", e);
    }
    LOG.error("Container heartbeat expired");
    response = new ContainerHeartbeatResponse(false);
    return response;
  }
Issues a heartbeat request to the coordinator
@return the corresponding {@link ContainerHeartbeatResponse}.
samza-core/src/main/java/org/apache/samza/container/ContainerHeartbeatClient.java