This has been observed once on 9 b119 promotion testing

test BasicTest.test(): failure
org.testng.internal.thread.ThreadTimeoutException: Method org.testng.internal.TestNGMethod.test() didn't finish within the time-out 30000
at jdk.internal.misc.Unsafe.park(java.base@9-ea/Native Method)
at java.util.concurrent.locks.LockSupport.park(java.base@9-ea/LockSupport.java:190)
at java.util.concurrent.CompletableFuture$Signaller.block(java.base@9-ea/CompletableFuture.java:1747)
at java.util.concurrent.ForkJoinPool.managedBlock(java.base@9-ea/ForkJoinPool.java:3443)
at java.util.concurrent.CompletableFuture.waitingGet(java.base@9-ea/CompletableFuture.java:1776)
at java.util.concurrent.CompletableFuture.join(java.base@9-ea/CompletableFuture.java:1986)
at BasicTest.simpleTest(BasicTest.java:244)
at BasicTest.test(BasicTest.java:98)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(java.base@9-ea/Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(java.base@9-ea/NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9-ea/DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(java.base@9-ea/Method.java:531)
at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84)
at org.testng.internal.InvokeMethodRunnable.runOne(InvokeMethodRunnable.java:46)
at org.testng.internal.InvokeMethodRunnable.run(InvokeMethodRunnable.java:37)
at java.util.concurrent.Executors$RunnableAdapter.call(java.base@9-ea/Executors.java:514)
at java.util.concurrent.FutureTask.run(java.base@9-ea/FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@9-ea/ThreadPoolExecutor.java:1158)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@9-ea/ThreadPoolExecutor.java:632)
at java.lang.Thread.run(java.base@9-ea/Thread.java:804)