Compute sizes of classes loaded in perm gen

[Sergei Mihhailov]

Greetings,

I'm writing special purpose java agent to compute sizes of classes 
loaded in perm gen. Basically reimplementing some functionality of "jmap 
-permstat". But in order to do that, I need to get instances of 
InstanceKlass for all loaded classes.

I've looked up PermStat source code, and tried to use it internally in 
my agent using its start() method. This attempt failed : 
"sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process"

Is it somehow possible to compute sizes of classes loaded in perm gen?


Thanks,
Sergei