Test java/lang/management/ThreadMXBean/Locks.java failed with NullPointerException

----------System.out:(16/487)----------
LockAThread about to block on OBJB
LockBThread about to block on OBJC
LockAThread blocked on Locks$ObjectB@27ff6391
ownerInfo = "LockBThread" daemon prio=5 Id=23 BLOCKED on Locks$EnhancedWaiter@66397cfd owned by "MainThread" Id=21


 Owner = LockBThread id = 23
LockBThread Id = 23 blocked on Locks$EnhancedWaiter@66397cfd
ownerInfo = "MainThread" prio=5 Id=21 RUNNABLE


 Owner = MainThread id = 21
MainThread Id = 21 blocked on null

LockAThread blocked on Locks$ObjectB@27ff6391

----------System.err:(14/939)----------
java.lang.NullPointerException: Cannot invoke "java.lang.management.ThreadInfo.getThreadId()" because "<local13>" is null
at Locks.findOwnerInfo(Locks.java:425)
at Locks.doCheck(Locks.java:470)
at Locks.findThreadsBlockedOn(Locks.java:443)
at Locks.main(Locks.java:385)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:573)
at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
at java.base/java.lang.Thread.run(Thread.java:1576)