I noticed a small usability regression apparently introduced by JDK-8156500.
When the ReferenceHandler thread is idle (i.e. almost always) its stack trace misleadingly suggests it is RUNNABLE

"Reference Handler" daemon prio=10 Id=2 RUNNABLE
at java.base@14-ea/java.lang.ref.Reference.waitForReferencePendingList(Native Method)
at java.base@14-ea/java.lang.ref.Reference.processPendingReferences(Reference.java:241)
at java.base@14-ea/java.lang.ref.Reference$ReferenceHandler.run(Reference.java:213)

it would be nice if the user-visible java thread state and lock info was the same as if it was blocked inside Object.wait, giving stack traces something like

"Reference Handler" daemon prio=10 Id=2 WAITING on VM heap lock

which would make "dump all threads" output less confusing.