Does Java VisualVM gives correct Heap Size of heap dump (.hprof file)

Question

I am analyzing a OutOfMemory issue. I got a dump of 800 MB (.hprof file) when i open it in MAT it shows heap size 53.2 MB as below

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Same dump i opened in Java VisualVM and I see Heap size around 769 MB

  Date taken: Tue Mar 18 05:25:59 IST 2014
    File: C:\Users\ABC\Desktop\Memory\MemoryDump.hprof
    File size: 789.1 MB
    Total bytes: 768,683,549
    Total classes: 9,288
    Total instances: 7,081,010
    Classloaders: 2,924
    GC roots: 2,496
    Number of objects pending for finalization: 0

I read one article which shows MAT skips unreachable objects so doesnt report exact heap size.

What does Total Bytes of VisulaVM shows here : Heap Size or (Heap + Non Heap size) or anything else?

Tomas Hurka Tomas Hurka · Accepted Answer · 2014-05-02T09:15:43

0

votes

Total Bytes is the sum of the size of all the objects in the heap dump.

Does Java VisualVM gives correct Heap Size of heap dump (.hprof file)

2 Answers