I'm a newcomer in Jenkins, and trying to debug a groovy script which works well on another environment here.

The script has to be executed when there is an attempt to merge a branch into develop.

I spotted the line in scrip where it cast exception -

def versionTemplateList = getJiraVersions(PULL_REQUEST_TO_BRANCH)

def firstPart= versionTemplateList.get(0)

The problem here is that versionTemplateList is NULL after its initialisation.

PULL_REQUEST_TO_BRANCH is not null. I checked that it has some value.

These the errors I've got -

java.lang.NullPointerException: Cannot invoke method get() on null object        at org.codehaus.groovy.runtime.NullObject.invokeMethod(NullObject.java:91)        at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:48)        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)        at org.codehaus.groovy.runtime.callsite.NullCallSite.call(NullCallSite.java:35)        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)        at org.kohsuke.groovy.sandbox.impl.Checker$1.call(Checker.java:158)        at org.kohsuke.groovy.sandbox.impl.Checker.checkedCall(Checker.java:160)        at com.cloudbees.groovy.cps.sandbox.SandboxInvoker.methodCall(SandboxInvoker.java:17)        at WorkflowScript.run(WorkflowScript:31)        at __cps.transform__(Native Method)        at com.cloudbees.groovy.cps.impl.ContinuationGroup.methodCall(ContinuationGroup.java:57)        at com.cloudbees.groovy.cps.impl.FunctionCallBlock$ContinuationImpl.dispatchOrArg(FunctionCallBlock.java:109)        at com.cloudbees.groovy.cps.impl.FunctionCallBlock$ContinuationImpl.fixArg(FunctionCallBlock.java:82)        at sun.reflect.GeneratedMethodAccessor390.invoke(Unknown Source)        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)        at java.lang.reflect.Method.invoke(Method.java:498)        at com.cloudbees.groovy.cps.impl.ContinuationPtr$ContinuationImpl.receive(ContinuationPtr.java:72)        at com.cloudbees.groovy.cps.impl.ConstantBlock.eval(ConstantBlock.java:21)        at com.cloudbees.groovy.cps.Next.step(Next.java:83)        at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:174)        at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:163)        at org.codehaus.groovy.runtime.GroovyCategorySupport$ThreadCategoryInfo.use(GroovyCategorySupport.java:129)        at org.codehaus.groovy.runtime.GroovyCategorySupport.use(GroovyCategorySupport.java:268)        at com.cloudbees.groovy.cps.Continuable.run0(Continuable.java:163)        at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.access$101(SandboxContinuable.java:34)        at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.lambda$run0$0(SandboxContinuable.java:59)        at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.GroovySandbox.runInSandbox(GroovySandbox.java:241)        at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.run0(SandboxContinuable.java:58)        at org.jenkinsci.plugins.workflow.cps.CpsThread.runNextChunk(CpsThread.java:182)        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:332)        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$200(CpsThreadGroup.java:83)        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:244)        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:232)        at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:64)        at java.util.concurrent.FutureTask.run(FutureTask.java:266)        at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:131)        at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)        at jenkins.security.ImpersonatingExecutorService$1.run(ImpersonatingExecutorService.java:59)        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)        at java.util.concurrent.FutureTask.run(FutureTask.java:266)        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)        at java.lang.Thread.run(Thread.java:748)Finished: FAILURE

It would be great if someone point me any clue.