How can we calculate no. of instances in a java program ?

Hi,
I want to know that
How can we calculate no. of instances in a java program ?
Actually I just want to calculate number of live instances in a program at any time...
Thanx in Advance
Vijay

Been asked a few times in this forum.
Try having a search.
One way, in brief, is to instrument your classes so that constructors update a per-type counter, and enqueue a PhantomReference for the instance.
When you pop from an associated ReferenceQueue, decrement the counter for the no longer reachable type.
Once you have this, you can query instance counts per type, or globably etc.
We maintain a model which can be remotely queried - and display results over time using JGraph. Gives a fairly non-intrusive way to spot and narrow down the cause of memory leaks in a large application.

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[email protected]
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