I don't know what kind of tasks are you talking about but let's assume you are running some pods

you can do

watch 'kubectl get pods | grep <name of the pod>'

or

kubectl get pods -w

It will not be the full name of course as most of the time the pods get random names if you are running nginx replica or deployment your pods will end up with something like nginx-1696122428-ftjvy so you will want to do

watch 'kubectl get pods | grep nginx'

You can replace the pods with whatever job you are doing i.e (rc,svc,deployments....)

$ kubectl wait --for=condition=complete --timeout=600s job/myjob

I found that the JobStatus does not get updated while polling using job.getStatus() Even if the status changes while checking from the command prompt using kubectl.

To get around this, I reload the job handler:

    client.extensions().jobs()
                       .inNamespace(myJob.getMetadata().getNamespace())
                       .withName(myJob.getMetadata().getName())
                       .get();

My loop to check the job status looks like this:

    KubernetesClient client = new DefaultKubernetesClient(config);
    Job myJob = client.extensions().jobs()
                      .load(new FileInputStream("/path/x.yaml"))
                      .create();
    boolean jobActive = true;
    while(jobActive){
        myJob = client.extensions().jobs()
                .inNamespace(myJob.getMetadata().getNamespace())
                .withName(myJob.getMetadata().getName())
                .get();
        JobStatus myJobStatus = myJob.getStatus();
        System.out.println("==================");
        System.out.println(myJobStatus.toString());

        if(myJob.getStatus().getActive()==null){
            jobActive = false;
        }
        else {
            System.out.println(myJob.getStatus().getActive());
            System.out.println("Sleeping for a minute before polling again!!");
            Thread.sleep(60000);
        }
    }

    System.out.println(myJob.getStatus().toString());

Hope this helps

You can use NewSharedInformer method to watch the jobs' statuses. Not sure how to write it in Java, here's the golang example to get your job list periodically:

type ClientImpl struct {
    clients *kubernetes.Clientset
}

type JobListFunc func() ([]batchv1.Job, error)

var (
    jobsSelector = labels.SelectorFromSet(labels.Set(map[string]string{"job_label": "my_label"})).String()
)


func (c *ClientImpl) NewJobSharedInformer(resyncPeriod time.Duration) JobListFunc {
    var once sync.Once
    var jobListFunc JobListFunc

    once.Do(
        func() {
            restClient := c.clients.BatchV1().RESTClient()
            optionsModifer := func(options *metav1.ListOptions) {
                options.LabelSelector = jobsSelector
            }
            watchList := cache.NewFilteredListWatchFromClient(restClient, "jobs", metav1.NamespaceAll, optionsModifer)
            informer := cache.NewSharedInformer(watchList, &batchv1.Job{}, resyncPeriod)

            go informer.Run(context.Background().Done())

            jobListFunc = JobListFunc(func() (jobs []batchv1.Job, err error) {
                for _, c := range informer.GetStore().List() {
                    jobs = append(jobs, *(c.(*batchv1.Job)))
                }
                return jobs, nil
            })
        })

    return jobListFunc
}

Then in your monitor you can check the status by ranging the job list:

func syncJobStatus() {
    jobs, err := jobListFunc()
    if err != nil {
        log.Errorf("Failed to list jobs: %v", err)
        return
    }

    // TODO: other code

    for _, job := range jobs {
        name := job.Name
        // check status...
    }
}

Since you said Java; you can use kubernetes java bindings from fabric8 to start the job and add a watcher:

KubernetesClient k = ...
k.extensions().jobs().load(yaml).watch (new Watcher <Job>() {

  @Override
  public void onClose (KubernetesClientException e) {}

  @Override
  public void eventReceived (Action a, Job j) {
    if(j.getStatus().getSucceeded()>0)
      System.out.println("At least one job attempt succeeded");
    if(j.getStatus().getFailed()>0)
      System.out.println("At least one job attempt failed");
  }
});

You did not mention what is actually checking the job completion, but instead of waiting blindly and hope for the best you should keep polling the job status inside a loop until it becomes "Completed".