When we use this plugin in the pipeline, we got a NullPointerException, we want to use credentials (created in the same folder as the pipeline project so other people can't use), as shown below. We are using Jenkins 2.7.1.

stage 'Promote'

nexusArtifactUploader artifactId: a, credentialsId: '03061789-shortened-1ed6f456', file: a + '.zip', groupId: g, nexusPassword: '', nexusUrl: 'invnexus.mycompany.com/nexus', nexusUser: '', packaging: 'zip', protocol: 'http', repository: 'otpp-releases', version: new_version

D:\public\workspace\Release\Promote@2>Powershell -Command "Add-Type -Assembly System.IO.Compression.FileSystem; System.IO.Compression.ZipFile::CreateFromDirectory(\"stage\", \"pmer.zip\", System.IO.Compression.CompressionLevel::Optimal, $false)" Pipeline nexusArtifactUploader
Pipeline }
Pipeline // ws
Pipeline }
Pipeline // node
Pipeline End of Pipeline
java.lang.NullPointerException
at sp.sd.nexusartifactuploader.steps.NexusArtifactUploaderStep.getUsername(NexusArtifactUploaderStep.java:153)
at sp.sd.nexusartifactuploader.steps.NexusArtifactUploaderStep$Execution.run(NexusArtifactUploaderStep.java:276)
at sp.sd.nexusartifactuploader.steps.NexusArtifactUploaderStep$Execution.run(NexusArtifactUploaderStep.java:250)
at org.jenkinsci.plugins.workflow.steps.AbstractSynchronousNonBlockingStepExecution$1$1.call(AbstractSynchronousNonBlockingStepExecution.java:52)
at hudson.security.ACL.impersonate(ACL.java:213)
at org.jenkinsci.plugins.workflow.steps.AbstractSynchronousNonBlockingStepExecution$1.run(AbstractSynchronousNonBlockingStepExecution.java:49)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Finished: FAILURE