NullPointerException when calling Kubectl.top on pods when one of the pods is down

[c4lm]

Describe the bug
NullPointerException when calling Kubectl.top if one pod is in erroneous state or down. Stacktrace:

java.lang.NullPointerException: Cannot invoke "io.kubernetes.client.custom.PodMetrics.getContainers()" because "podMetrics" is null
	at io.kubernetes.client.extended.kubectl.KubectlTop.podMetricSum(KubectlTop.java:141)
	at io.kubernetes.client.extended.kubectl.KubectlTop$2.compare(KubectlTop.java:166)
	at io.kubernetes.client.extended.kubectl.KubectlTop$2.compare(KubectlTop.java:160)
	at java.base/java.util.TimSort.countRunAndMakeAscending(TimSort.java:355)
	at java.base/java.util.TimSort.sort(TimSort.java:220)
	at java.base/java.util.Arrays.sort(Arrays.java:1307)
	at java.base/java.util.ArrayList.sort(ArrayList.java:1805)
	at java.base/java.util.Collections.sort(Collections.java:178)
	at io.kubernetes.client.extended.kubectl.KubectlTop.topPods(KubectlTop.java:158)
	at io.kubernetes.client.extended.kubectl.KubectlTop.execute(KubectlTop.java:68)

Client Version
io.kubernetes:client-java:23.0.0
io.kubernetes:client-java-extended:23.0.0

Kubernetes Version
1.30

Server Version: version.Info{Major:"1", Minor:"30+", GitVersion:"v1.30.11-eks-bcf3d70", GitCommit:"2fa190a24584e3b061e4c94d3b4d1608e34e5e3b", GitTreeState:"clean", BuildDate:"2025-03-24T21:51:28Z", GoVersion:"go1.23.6", Compiler:"gc", Platform:"linux/amd64"}

Java Version
Java 23

To Reproduce
Steps to reproduce the behavior:

1. Have a pod that is down, completed, or in Error state, e.g. deploy a pod with an image that doesn't exist.
2. Call Kubectl.top on pods:

public List<Pair<V1Pod, PodMetrics>> getPodUsage(String namespace) throws KubectlException {
    return Kubectl.top(V1Pod.class, PodMetrics.class).namespace(namespace).execute();
  }

Expected behavior
Just like in the CLI, I expect to get pod metrics for pods which are up.

Server (please complete the following information):

• OS: amazonlinux:2023
• Environment: container in k8s
• Cloud: AWS

Additional context
Same happens on library version 18.0.1.

[Spurgeon008]

@c4lm Can i do this is anyone working on it ?

[brendandburns]

@Spurgeon008 feel free to send a PR no one is working on this.

[c4lm]

@c4lm Can i do this is anyone working on it ?

Please go ahead. I only opened this because I saw that nobody else reported the issue for the past 2 years (since there are ways around it).

[shreyas-0203]

Hii, @c4lm
I just want to give a try about it, as it looks interesting issue,
Can I go for it or the issue get resolved?

[c4lm]

🤷