groovy.lang.GroovyRuntimeException: Failed to create Script instance for class: class WorkflowScript. Reason: java.lang.NullPointerException
	at org.codehaus.groovy.runtime.InvokerHelper.createScript(InvokerHelper.java:430)
	at groovy.lang.GroovyShell.parse(GroovyShell.java:743)
	at org.jenkinsci.plugins.workflow.cps.CpsGroovyShell.reparse(CpsGroovyShell.java:67)
	at org.jenkinsci.plugins.workflow.cps.CpsFlowExecution.parseScript(CpsFlowExecution.java:410)
	at org.jenkinsci.plugins.workflow.cps.CpsFlowExecution.start(CpsFlowExecution.java:373)
	at org.jenkinsci.plugins.workflow.job.WorkflowRun.run(WorkflowRun.java:213)
	at hudson.model.ResourceController.execute(ResourceController.java:98)
	at hudson.model.Executor.run(Executor.java:410)
Caused by: java.lang.NullPointerException
	at org.jenkinsci.plugins.workflow.cps.CpsScript.$build(CpsScript.java:137)
	at org.jenkinsci.plugins.workflow.cps.CpsScript.$buildNoException(CpsScript.java:148)
	at org.jenkinsci.plugins.workflow.cps.CpsScript.getProperty(CpsScript.java:125)
	at org.codehaus.groovy.runtime.callsite.PogoGetPropertySite.getProperty(PogoGetPropertySite.java:47)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGroovyObjectGetProperty(AbstractCallSite.java:231)
	at WorkflowScript.<init>(WorkflowScript:...)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
	at java.lang.Class.newInstance(Class.java:442)
	at org.codehaus.groovy.runtime.InvokerHelper.createScript(InvokerHelper.java:408)
	... 7 more