How to dump Permgen?

jvm profiling permgen
Vikas Madhusudana picture Vikas Madhusudana · Nov 2, 2010 · Viewed 17.9k times · Source

I wanted to take the dump of the Permgen of a application server.

I do not want to use -XX:+TraceClassLoading -XX:+TraceClassUnloading as i do not want to restart the server, Neither i want to use jconsole.

I there any tool like jmap(used to heap dump didnt find any option for permgen) to get the permgen so that i can supply only the pid.

Answer

Guillaume Coté picture Guillaume Coté · May 25, 2011 
jmap -permstat <pid>

is going to produce an output like that : 

30337 intern Strings occupying 2746200 bytes.
class_loader    classes bytes   parent_loader   alive?  type

<bootstrap> 2031    7253392   null      live    <internal>
0x517474f0  1   1760      null      dead    sun/reflect/DelegatingClassLoader@0x43f95d38
0x4f83f670  1   1744    0x4ebfb8e8  dead    sun/reflect/DelegatingClassLoader@0x43f95d38
[...]

total = 287 10020   35889952        N/A     alive=3, dead=284       N/A

This is not a full dump, but doing that is going to allow you to do some investigation.

I am still looking on how to find more information.

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