When heap dump is produced using:

$ java -agentlib:hprof=cpu=samples,format=b,file=samples.dump -jar jdk/demo/jfc/Notepad/Notepad.jar
Dumping CPU usage by sampling running threads ... done.

jhat displays the following exception:

$ jhat samples.dump
Reading from samples.dump...
Dump file created Wed Oct 24 10:35:39 LSD 2007
Snapshot read, resolving...
Resolving 0 objects...
WARNING: hprof file does not include java.lang.Class!
WARNING: hprof file does not include java.lang.String!
WARNING: hprof file does not include java.lang.ClassLoader!
Chasing references, expect 0 dots
Eliminating duplicate references
Snapshot resolved.
Started HTTP server on port 7000
Server is ready.
Exception in thread "Thread-0" java.lang.NullPointerException
        at com.sun.tools.hat.internal.model.Snapshot.getFinalizerObjects(Snapshot.java:393)
        at com.sun.tools.hat.internal.server.FinalizerSummaryQuery.run(FinalizerSummaryQuery.java:26)
        at com.sun.tools.hat.internal.server.HttpReader.run(HttpReader.java:181)
        at java.lang.Thread.run(Thread.java:619)

The finalizers page is empty.

The same error occurs when cpu=times is used for dumping the heap.