Just tried the Object Count after GC events in JDK8. I get multiple events for the same class (from the same GC) with different information:

Class java.lang.management.PlatformComponent[]
Count 107
GC ID 325
Total Size 7.29 kB

Class java.lang.management.PlatformComponent[]
Count 2
GC ID 325
Total Size 80 bytes

Class java.lang.management.PlatformComponent[]
Count 1,030,550
GC ID 325
Total Size 71.31 MB

.. and so on. I was under the impression that these should be aggregated.

Same goes for the Object Count event.