Number of objects?

[Mike Shn]

Does it possible in Java to use come command or function to find how many objects or instances were created when a program was running?

Thanks in advance

[Jessica Sant]

There are profilers that can be used for this purpose -- its normally done when you're trying to optimize your code (Object creation is a very expensive process). Check out something like Sitraka's JProbe.

[Peter Tran]

Mike,
Not that I know of. You can create your own class ReferenceNew {} which wraps and returns you an actual. Within this ReferenceNew class, you can maintain a count of objects you created with new. It's easy if you want to keep a count of objects allocated since your program started, but it gets more complicated if you want to keep an accurate count of what objects are still active and the number objects that have been collected. Then you'll have to do some fancy stuff with the finalize() method, which I don't recommend doing unless you really need it.
You can look at the various profilers for Java. They do a very good job of keeping reference counts.
-Peter