Occur NullPointerException when using SharedInformers.stopAllRegisteredInformers() and the KubernetesClient.close()

[coderzc]

Occur NullPointerException when using SharedInformers.stopAllRegisteredInformers() and the KubernetesClient.close()

if (this.informerFactory != null) {
   this.informerFactory.stopAllRegisteredInformers();
}

if (this.kubeClient != null) {
    this.kubeClient.close();
}

The exception information:

java.lang.NullPointerException: null
	at java.util.ArrayList.<init>(ArrayList.java:178) ~[?:1.8.0_281]
	at io.fabric8.kubernetes.client.informers.cache.SharedProcessor.distribute(SharedProcessor.java:83) ~[kubernetes-client-5.5.0.jar:?]
	at io.fabric8.kubernetes.client.informers.cache.ProcessorStore.update(ProcessorStore.java:44) ~[kubernetes-client-5.5.0.jar:?]
	at io.fabric8.kubernetes.client.informers.cache.Reflector$ReflectorWatcher.eventReceived(Reflector.java:146) ~[kubernetes-client-5.5.0.jar:?]
	at io.fabric8.kubernetes.client.informers.cache.Reflector$ReflectorWatcher.eventReceived(Reflector.java:121) ~[kubernetes-client-5.5.0.jar:?]
	at io.fabric8.kubernetes.client.utils.WatcherToggle.eventReceived(WatcherToggle.java:49) ~[kubernetes-client-5.5.0.jar:?]
	at io.fabric8.kubernetes.client.dsl.internal.AbstractWatchManager.eventReceived(AbstractWatchManager.java:176) ~[kubernetes-client-5.5.0.jar:?]
	at io.fabric8.kubernetes.client.dsl.internal.AbstractWatchManager.onMessage(AbstractWatchManager.java:232) [kubernetes-client-5.5.0.jar:?]
	at io.fabric8.kubernetes.client.dsl.internal.WatcherWebSocketListener.onMessage(WatcherWebSocketListener.java:93) [kubernetes-client-5.5.0.jar:?]
	at okhttp3.internal.ws.RealWebSocket.onReadMessage(RealWebSocket.java:323) [okhttp-3.12.12.jar:?]
	at okhttp3.internal.ws.WebSocketReader.readMessageFrame(WebSocketReader.java:219) [okhttp-3.12.12.jar:?]
	at okhttp3.internal.ws.WebSocketReader.processNextFrame(WebSocketReader.java:105) [okhttp-3.12.12.jar:?]
	at okhttp3.internal.ws.RealWebSocket.loopReader(RealWebSocket.java:274) [okhttp-3.12.12.jar:?]
	at okhttp3.internal.ws.RealWebSocket$2.onResponse(RealWebSocket.java:214) [okhttp-3.12.12.jar:?]
	at okhttp3.RealCall$AsyncCall.execute(RealCall.java:203) [okhttp-3.12.12.jar:?]
	at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32) [okhttp-3.12.12.jar:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_281]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_281]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_281]

[rohanKanojia]

How can we reproduce this error? What kind of informers did you register into SharedInformerFactory which caused this NPE?

[coderzc]

How can we reproduce this error? What kind of informers did you register into SharedInformerFactory which caused this NPE?

It is an occasional error, kind of register into SharedInformerFactory include Job、ConfigMap、CustomResource

[coderzc]

@rohanKanojia I have a question the SharedInformerFactory.stopAllRegisteredInformers() whether is blocking until sharedInformer complete shutdown.