jdk/jshell/ExecutionControlTest.java failed intermittently with NPE

----------System.out:(71/4005)----------
[TestNG] Running:
  jdk/jshell/ExecutionControlTest.java

config ExecutionControlTest.setUp(): success
test ExecutionControlTest.classesDeclaration(): success
config KullaTesting.tearDown(): success
config ExecutionControlTest.setUp(): success
test ExecutionControlTest.interfaceTest(): failure
java.lang.NullPointerException
at LocalExecutionControl.invoke(LocalExecutionControl.java:174)
at jdk.jshell.Eval.declare(jdk.jshell@9-ea/Eval.java:458)
at jdk.jshell.Eval.declare(jdk.jshell@9-ea/Eval.java:434)
at jdk.jshell.Eval.processExpression(jdk.jshell@9-ea/Eval.java:290)
at jdk.jshell.Eval.eval(jdk.jshell@9-ea/Eval.java:117)
at jdk.jshell.JShell.eval(jdk.jshell@9-ea/JShell.java:393)
at KullaTesting.lambda$assertEval$1(KullaTesting.java:367)
at KullaTesting.checkEvents(KullaTesting.java:446)
at KullaTesting.assertEval(KullaTesting.java:367)
at KullaTesting.assertEval(KullaTesting.java:361)
at KullaTesting.assertEval(KullaTesting.java:332)
at ExecutionControlTest.interfaceTest(ExecutionControlTest.java:97)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(java.base@9-ea/Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(java.base@9-ea/NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9-ea/DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(java.base@9-ea/Method.java:531)
at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84)
at org.testng.internal.Invoker.invokeMethod(Invoker.java:714)
at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901)
at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231)
at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:127)
at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:111)
at org.testng.TestRunner.privateRun(TestRunner.java:767)
at org.testng.TestRunner.run(TestRunner.java:617)
at org.testng.SuiteRunner.runTest(SuiteRunner.java:334)
at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:329)
at org.testng.SuiteRunner.privateRun(SuiteRunner.java:291)
at org.testng.SuiteRunner.run(SuiteRunner.java:240)
at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
at org.testng.TestNG.runSuitesSequentially(TestNG.java:1224)
at org.testng.TestNG.runSuitesLocally(TestNG.java:1149)
at org.testng.TestNG.run(TestNG.java:1057)
at com.sun.javatest.regtest.TestNGAction$TestNGRunner.main(TestNGAction.java:220)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(java.base@9-ea/Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(java.base@9-ea/NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9-ea/DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(java.base@9-ea/Method.java:531)
at com.sun.javatest.regtest.agent.MainActionHelper$SameVMRunnable.run(MainActionHelper.java:226)
at java.lang.Thread.run(java.base@9-ea/Thread.java:843)
config KullaTesting.tearDown(): success
config ExecutionControlTest.setUp(): success
test ExecutionControlTest.methodOverload(): success
config KullaTesting.tearDown(): success
config ExecutionControlTest.setUp(): success
test ExecutionControlTest.testExprSanity(): success
config KullaTesting.tearDown(): success
config ExecutionControlTest.setUp(): success
test ExecutionControlTest.testImportOnDemand(): success
config KullaTesting.tearDown(): success
config ExecutionControlTest.setUp(): success
test ExecutionControlTest.variables(): success
config KullaTesting.tearDown(): success
config ExecutionControlTest.setUp(): success
test ExecutionControlTest.verifyLocal(): success
config KullaTesting.tearDown(): success

===============================================
jdk/jshell/ExecutionControlTest.java
Total tests run: 7, Failures: 1, Skips: 0
===============================================