Cache doesn't find getMetadata method although it is present

[ctron]

The Cache implementation doesn't find the getMetadata method although it is present:

2019-12-10T14:32:21.596Z ERROR [ReflectorRunnable] Failure in list-watch: java.lang.ReflectiveOperationException: java.lang.NoSuchMethodException: io.enmasse.iot.model.v1.IoTProject.getMetadata()
java.lang.RuntimeException: java.lang.ReflectiveOperationException: java.lang.NoSuchMethodException: io.enmasse.iot.model.v1.IoTProject.getMetadata()
	at io.fabric8.kubernetes.client.informers.cache.Cache.metaNamespaceKeyFunc(Cache.java:365)
	at io.fabric8.kubernetes.client.informers.cache.DeltaFIFO.keyOf(DeltaFIFO.java:381)
	at io.fabric8.kubernetes.client.informers.cache.DeltaFIFO.replace(DeltaFIFO.java:165)
	at io.fabric8.kubernetes.client.informers.cache.ReflectorRunnable.syncWith(ReflectorRunnable.java:145)
	at io.fabric8.kubernetes.client.informers.cache.ReflectorRunnable.run(ReflectorRunnable.java:69)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305)
	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.ReflectiveOperationException: java.lang.NoSuchMethodException: io.enmasse.iot.model.v1.IoTProject.getMetadata()
	at io.fabric8.kubernetes.client.utils.ReflectUtils.objectMetadata(ReflectUtils.java:31)
	at io.fabric8.kubernetes.client.informers.cache.Cache.metaNamespaceKeyFunc(Cache.java:355)
	... 10 more
Caused by: java.lang.NoSuchMethodException: io.enmasse.iot.model.v1.IoTProject.getMetadata()
	at java.base/java.lang.Class.getDeclaredMethod(Class.java:2475)
	at io.fabric8.kubernetes.client.utils.ReflectUtils.objectMetadata(ReflectUtils.java:28)
	... 11 more

This is due to the fact that ReflectUtils uses getDeclaredMethod, which will only find methods which are directly declared on the class:

kubernetes-client/kubernetes-client/src/main/java/io/fabric8/kubernetes/client/utils/ReflectUtils.java

Lines 28 to 29 in e2a8c9f

	Method mdField = obj.getClass().getDeclaredMethod("getMetadata");
	return (ObjectMeta) mdField.invoke(obj);

Instead of doing reflection, the code should check for instanceof HasMetadata and maybe then use Class#getMethod.