Duplication:

1. Go to http://<jenkins>/computer/<node>/script
2. Run:

   import org.jenkinsci.plugins.p4.workspace.StreamWorkspaceImpl;
   import org.jenkinsci.plugins.p4.groovy.P4Groovy;
   
   def ws = new StreamWorkspaceImpl('none', false, '//Stream_Depot/Main', 'job1-temp-branch1')
   def p4 = new P4Groovy('bad credential', null, ws, new FilePath(new File('workspace')))
   def result = p4.run('status')

1. The error message returned is 'hudson.AbortException: P4: Task Exception: null'

This can also be duplicated by using a bad credential in a Jenkinsfile using the normal syntax:

def ws = [$class: 'StreamWorkspaceImpl', charset: 'none', format: env.JOB_NAME + '-temp-' + env.BRANCH_NAME, pinHost: false, streamName: '//Stream_Depot/' + env.BRANCH_NAME]
def p4 = p4(credential: 'bad credential', workspace: ws)
def result = p4.run('streams')

Expected result:

An error message stating that the credential is not found.