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Memory calculations...

 
Chinmay Bajikar
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Hi,
I have to estimate how much mem a particular object is taking at runtime.
I have tried JProfiler,but have found that it is quiet an heavy application in itself.
Is there any freeware which will give me a decent estimation of how much increase/decrease in mem have been caused by the changes made to the code by me?
Thanks,
Chinmay.....
 
Dirk Schreckmann
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Take a look at JavaWorld's Java Tip 130: Do you know your data size?.
 
Chinmay Bajikar
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Hi Dirk,
I have gone thru the article and found it to be informative.
But didnt understand this one statement by Valdimir.....
"I am not sure why, but it's possible creating and destroying a method call-stack frame causes a change in the reachability root set and prompts the garbage collector to work harder."
Can u shed some light on this???
Thanks and regards,
Chinmay..

 
John O'Hanley
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Here is some more <a href="http://www.javapractices.com/Topic83.cjp">example code</a> for this
task. It follows the style of the book "Java Platform Performance", by Wilson and Kesselman.
 
Dirk Schreckmann
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Originally posted by Chinmay Bajikar:
Hi Dirk,
I have gone thru the article and found it to be informative.
But didnt understand this one statement by Valdimir.....
"I am not sure why, but it's possible creating and destroying a method call-stack frame causes a change in the reachability root set and prompts the garbage collector to work harder."
Can u shed some light on this???

I'm not completely familiar with the details of garbage collection and JVM implementations. I believe that what the author is suggesting is that when a method terminates, this might send a special signal to the garbage collector that it consider running as some objects in memory were possibly just made unreachable (i.e. aren't being used any more).
 
Consider Paul's rocket mass heater.
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