Heap dump file size vs heap size

[Michal Slocinski]

Hi,

Do you know how heap dump file size is related to heap size itself?
I've multiple heap dumps created using jmap on Solaris using Sun JVM
1.5.0_09 and somehow filesize doesn't relate to heap size itself.

Disproportions are quite big actually (even 500MB - 1GB)

Michal

 

[GArlington]

Hi,

Do you know how heap dump file size is related to heap size itself?
I've multiple heap dumps created using jmap on Solaris using Sun JVM
1.5.0_09 and somehow filesize doesn't relate to heap size itself.

Disproportions are quite big actually (even 500MB - 1GB)

Michal

Look ta java.lang.Runtime class, see what it can give you...
Think about how the heap behaves, how gc() is working depending on
various settings, this may give you few clues why the heap size may
NOT be related to heap dump file size (and do not forget that there is
always extra info in the dump file too)...