Held locks do not all show up in stacktraces

ForgottenLockTest.java

import java.util.*;
import java.util.concurrent.locks.*;

/*
  javac ForgottenLockTest.java
  java -cp . ForgottenLockTest
  ^\
*/

public class ForgottenLockTest  {

    public static void main(String[] args) 
    {   
        System.out.println("started");
        final ReadWriteLock lock = new ReentrantReadWriteLock();

        lock.writeLock().lock();

	new Thread() { public void run() {
	    System.out.println("thread started");
	    lock.writeLock().lock(); 
	    System.out.println("thread done"); 
	} } .start();

	while(true) {
	    try { Thread.sleep(1000); }
	    catch( InterruptedException e ) { break; }
	}

	System.out.println("main done");
    }
}

/*
** Note that there is no indication that the "main" thread holds the lock that "Thread-1" is waiting on.

Full thread dump Java HotSpot(TM) 64-Bit Server VM (20.8-b03-424 mixed mode):

"Thread-1" prio=5 tid=1050c4800 nid=0x10d101000 waiting on condition [10d100000]
   java.lang.Thread.State: WAITING (parking)
   at sun.misc.Unsafe.park(Native Method)
   - parking to wait for  <7f310f5e0> (a java.util.concurrent.locks.ReentrantReadWriteLock$NonfairSync)
   at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
   at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:811)
   at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:842)
   at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1178)
   at java.util.concurrent.locks.ReentrantReadWriteLock$WriteLock.lock(ReentrantReadWriteLock.java:807)
   at ForgottenLockTest$1.run(ForgottenLockTest.java:21)

"main" prio=5 tid=105000800 nid=0x100501000 waiting on condition [100500000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
   at java.lang.Thread.sleep(Native Method)
   at ForgottenLockTest.main(ForgottenLockTest.java:26)

*/

SingleThreadDeadlock.java

import java.util.*;
import java.util.concurrent.locks.*;

/*
  javac SingleThreadDeadlock.java
  java -cp . SingleThreadDeadlock
  ^						\

*/

public class SingleThreadDeadlock {
    public static void main(String[] args) {   
        System.out.println("starting");
        ReadWriteLock lock = new ReentrantReadWriteLock();

        lock.readLock().lock();
        lock.writeLock().lock();
        System.out.println("done");
    }
}

/*
Full thread dump Java HotSpot(TM) 64-Bit Server VM (20.8-b03-424 mixed mode):

"main" prio=5 tid=104000800 nid=0x100501000 waiting on condition [100500000]
   java.lang.Thread.State: WAITING (parking)
   at sun.misc.Unsafe.park(Native Method)
   - parking to wait for  <7f310f220> (a java.util.concurrent.locks.ReentrantReadWriteLock$NonfairSync)
   at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
   at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:811)
   at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:842)
   at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1178)
   at java.util.concurrent.locks.ReentrantReadWriteLock$WriteLock.lock(ReentrantReadWriteLock.java:807)
   at SingleThreadDeadlock.main(SingleThreadDeadlock.java:17)

*/