The java/lang/management/ThreadMXBean/Locks.java test seems to expect all threads returned by java.lang.management.ThreadMXBean#getAllThreadIds to still be alive in a subsequent call to java.lang.management.ThreadMXBean#getThreadInfo(long). Running the test on GraalVM sometimes fails with:

STDOUT:
LockBThread about to block on OBJC
LockAThread about to block on OBJB
Stack dump : Thread -> LockBThread
java.base/java.util.concurrent.Phaser.internalAwaitAdvance(Phaser.java:1063)
java.base/java.util.concurrent.Phaser.arriveAndAwaitAdvance(Phaser.java:685)
Locks$LockBThread.run(Locks.java:196)

STDERR:
java.lang.NullPointerException: Cannot invoke "java.lang.management.ThreadInfo.getLockName()" because "<local7>" is null
at Locks.doCheck(Locks.java:437)
at Locks.findThreadsBlockedOn(Locks.java:425)
at Locks.main(Locks.java:374)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:125)
at java.base/java.lang.Thread.run(Thread.java:1623)