This causes trouble for scripted pipelines testing, e.g. when using jenkins-spock library:
Could not initialize class org.jenkinsci.plugins.workflow.cps.CpsThread
java.lang.NoClassDefFoundError: Could not initialize class org.jenkinsci.plugins.workflow.cps.CpsThread
at org.jenkinsci.plugins.workflow.cps.CpsScript.<init>(CpsScript.java:69)
at org.spockframework.mock.runtime.MockInstantiator.instantiate(MockInstantiator.java:33)
at org.spockframework.mock.runtime.ProxyBasedMockFactory$CglibMockFactory.createMock(ProxyBasedMockFactory.java:155)
at org.spockframework.mock.runtime.ProxyBasedMockFactory.create(ProxyBasedMockFactory.java:68)
at org.spockframework.mock.runtime.JavaMockFactory.createInternal(JavaMockFactory.java:59)
at org.spockframework.mock.runtime.JavaMockFactory.create(JavaMockFactory.java:40)
at org.spockframework.mock.runtime.CompositeMockFactory.create(CompositeMockFactory.java:44)
at org.spockframework.lang.SpecInternals.createMock(SpecInternals.java:51)
at org.spockframework.lang.SpecInternals.createMockImpl(SpecInternals.java:296)
at org.spockframework.lang.SpecInternals.createMockImpl(SpecInternals.java:286)
at org.spockframework.lang.SpecInternals.SpyImpl(SpecInternals.java:161)
at com.homeaway.devtools.jenkins.testing.JenkinsPipelineSpecification.setup(JenkinsPipelineSpecification.groovy:1025)