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The hprof, histogram shows the number of object by class.

is this the total number of object that have ever been allocated during the life of the jvm ?

or is this the number of object where are currently on the heap ?

or is this the number of currently reachable object on the heap ?

trincot
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dmc
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1 Answers1

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It depends. If you're generating dump with "live" (for example jmap -histo:live PID) option it's number of reachable objects. In other case it's number of objects currently allocated on heap.

Jakub Kubrynski
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  • my hprof was generated on OOM using hprof=cpu=samples,depth=10 so I am now assuming it number of object currenlty allocated on the heap, and so reachable ? – dmc Jun 08 '15 at 20:50
  • @dmc AFAIK hprof=cpu show cpu usage, not objects histogram. Are you sure you're thinking about objects? – Jakub Kubrynski Jun 08 '15 at 21:07
  • yes I read this also, but I do see the histo and all the object and content ect, so maybe its not generated with the args i was thinking, but it is generated via a OOM. any way. thanks – dmc Jun 08 '15 at 21:24