Can't construct a java object for scalar tag:yaml.org,2002:timestamp; No String constructor found.

[mattnworb]

In an application using io.kubernetes:client-java:2.0.0, I have some code that queries a cluster to fetch pods that meet a certain condition and then transform the data in various ways.

In writing a test of this code, I am trying to (in my unit test) load YAML returned by kubectl get pod/foobar... -o yaml to construct a real-like V1Pod for the code-under-test to work with, with code like:

InputStream stream = this.getClass().getResourceAsStream("crashing-pod.yaml");
V1Pod pod;
try (InputStreamReader reader = new InputStreamReader(stream)) {
  pod = Yaml.loadAs(reader, V1Pod.class);
}

With crashing-pod.yaml looking like:

apiVersion: v1
kind: Pod
metadata:
  annotations:
    podpreset.admission.spotify.com/revision: 6104d05
  creationTimestamp: 2018-09-06T15:12:24Z
  ...

This throws an exception, seemingly because the snakeyaml reader is not configured to know how to deserialize strings into org.joda.time.DateTime instances:

Cannot create property=metadata for JavaBean=class V1Pod {
    apiVersion: v1
    kind: Pod
    metadata: null
    spec: null
    status: null
}
 in 'reader', line 1, column 1:
    apiVersion: v1
    ^
Cannot create property=creationTimestamp for JavaBean=class V1ObjectMeta {
    annotations: {podpreset.admission.spotify.com/revision=6104d05}
    clusterName: null
    creationTimestamp: null
    deletionGracePeriodSeconds: null
    deletionTimestamp: null
    finalizers: null
    generateName: null
    generation: null
    initializers: null
    labels: null
    name: null
    namespace: null
    ownerReferences: null
    resourceVersion: null
    selfLink: null
    uid: null
}
 in 'reader', line 4, column 3:
      annotations:
      ^
Can't construct a java object for scalar tag:yaml.org,2002:timestamp; No String constructor found. Exception=org.joda.time.DateTime.<init>(java.lang.String)
 in 'reader', line 6, column 22:
      creationTimestamp: 2018-09-06T15:12:24Z
                         ^

 in 'reader', line 4, column 3:
      annotations:
      ^


	at org.yaml.snakeyaml.constructor.Constructor$ConstructMapping.constructJavaBean2ndStep(Constructor.java:313)
	at org.yaml.snakeyaml.constructor.Constructor$ConstructMapping.construct(Constructor.java:190)
	at org.yaml.snakeyaml.constructor.Constructor$ConstructYamlObject.construct(Constructor.java:346)
	at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:184)
	at io.kubernetes.client.util.Yaml$CustomConstructor.constructObject(Yaml.java:272)
	at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:143)
	at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:129)
	at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:505)
	at org.yaml.snakeyaml.Yaml.loadAs(Yaml.java:465)
	at io.kubernetes.client.util.Yaml.loadAs(Yaml.java:207)
	at com.spotify.tugboat.apiservice.kubernetes.KubeInstallationStatusFetcherTest.testCrashLoopingPod(KubeInstallationStatusFetcherTest.java:158)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: Cannot create property=creationTimestamp for JavaBean=class V1ObjectMeta {
    annotations: {podpreset.admission.spotify.com/revision=6104d05}
    clusterName: null
    creationTimestamp: null
    deletionGracePeriodSeconds: null
    deletionTimestamp: null
    finalizers: null
    generateName: null
    generation: null
    initializers: null
    labels: null
    name: null
    namespace: null
    ownerReferences: null
    resourceVersion: null
    selfLink: null
    uid: null
}
 in 'reader', line 4, column 3:
      annotations:
      ^
Can't construct a java object for scalar tag:yaml.org,2002:timestamp; No String constructor found. Exception=org.joda.time.DateTime.<init>(java.lang.String)
 in 'reader', line 6, column 22:
      creationTimestamp: 2018-09-06T15:12:24Z
                         ^

	at org.yaml.snakeyaml.constructor.Constructor$ConstructMapping.constructJavaBean2ndStep(Constructor.java:313)
	at org.yaml.snakeyaml.constructor.Constructor$ConstructMapping.construct(Constructor.java:190)
	at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:184)
	at io.kubernetes.client.util.Yaml$CustomConstructor.constructObject(Yaml.java:272)
	at org.yaml.snakeyaml.constructor.Constructor$ConstructMapping.constructJavaBean2ndStep(Constructor.java:298)
	... 32 more
Caused by: org.yaml.snakeyaml.error.YAMLException: Can't construct a java object for scalar tag:yaml.org,2002:timestamp; No String constructor found. Exception=org.joda.time.DateTime.<init>(java.lang.String)
	at org.yaml.snakeyaml.constructor.Constructor$ConstructScalar.construct(Constructor.java:412)
	at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:184)
	at io.kubernetes.client.util.Yaml$CustomConstructor.constructObject(Yaml.java:272)
	at org.yaml.snakeyaml.constructor.Constructor$ConstructMapping.constructJavaBean2ndStep(Constructor.java:298)
	... 36 more
Caused by: java.lang.NoSuchMethodException: org.joda.time.DateTime.<init>(java.lang.String)
	at java.lang.Class.getConstructor0(Class.java:3082)
	at java.lang.Class.getDeclaredConstructor(Class.java:2178)
	at org.yaml.snakeyaml.constructor.Constructor$ConstructScalar.construct(Constructor.java:410)
	... 39 more