Spring Boot Dekorate Maven Quickstart throws NPE on k8s:apply

[rohanKanojia]

Description

When I'm running k8s:apply goal to apply manifests generated by dekorate to Kubernetes Cluster. I'm getting NullPointerException:

spring-boot-dekorate : $ mvn k8s:apply -Pkubernetes
[INFO] Scanning for projects...
[INFO] 
[INFO] ------< org.eclipse.jkube.quickstarts.maven:spring-boot-dekorate >------
[INFO] Building Eclipse JKube :: Quickstarts :: Maven :: Spring Boot - Dekorate 1.5.1
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- kubernetes-maven-plugin:1.5.1:apply (default-cli) @ spring-boot-dekorate ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  1.672 s
[INFO] Finished at: 2021-11-10T23:10:53+05:30
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.eclipse.jkube:kubernetes-maven-plugin:1.5.1:apply (default-cli) on project spring-boot-dekorate: null: MojoExecutionException: NullPointerException -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

NPE seems to be pointing to this line (items being null):

https://github.com/eclipse/jkube/blob/2a328258896d2079a3f3d8059c40b7cb141099da/jkube-kit/common/src/main/java/org/eclipse/jkube/kit/common/util/ResourceUtil.java#L97

This seems to be affecting all versions since v1.1.0. Quickstart is working for me on v1.1.0, but fails on all later versions. The problem seems to be coming from recent changes in ResourceUtil class that it can no longer handle multiple document manifests which are added by Dekorate:

---
apiVersion: "v1"
kind: "Service"
metadata:
  labels:
    app: "spring-boot-dekorate"
    decorated-by: "dekorate"
    version: "latest"
    group: "jkube"
---
apiVersion: "apps/v1"
kind: "Deployment"
metadata:
  labels:
    app: "spring-boot-dekorate"

It only seems to be accepting this format:

---
apiVersion: v1
kind: List
items:
- apiVersion: v1
  kind: Service
  metadata:
    annotations:

Info

• Eclipse JKube version : 1.5.1
• Maven version (mvn -v) :

Apache Maven 3.8.1 (05c21c65bdfed0f71a2f2ada8b84da59348c4c5d)
Maven home: /opt/apache-maven
Java version: 11.0.11, vendor: Oracle Corporation, runtime: /usr/java/jdk-11.0.11
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "5.14.14-300.fc35.x86_64", arch: "amd64", family: "unix"

• Kubernetes / Red Hat OpenShift setup and version : N/A

• If it's a bug, how to reproduce : Go to quickstarts/maven/spring-boot-dekorate and run mvn clean install k8s:apply -Pkubernetes you'll get NPE