RFR: 8007806: Need a Throwables performance counter

Nils Loodin nils.loodin at oracle.com
Tue Feb 19 10:57:07 UTC 2013

Hey Kasper!

You're right that there are methods that throw exceptions as a part of 
the normal program flow.

However, this number can be (and has been) used as a very high level 
telemetry for an application. Depending on exactly how large this number 
is, and how fast it is growing, something can be seen to be amis in the 
application. Paired together with data of what type of exceptions are 
being thrown, and from where, it can be useful for support to have this 

Nils Loodin

On 02/12/2013 06:28 PM, Kasper Nielsen wrote:
> Jrockit mission control supports an "exception count" based on exception
> type.
> I have found the approach of just counting the total number of exception
> completely useless.
> Mainly because there are methods that throw exceptions as part of the
> normal flow. For example, Class.forName() is commonly used to test
> whether or not a certain
> class is on the classpath.
> And most developers will cringe whenever they see an exception count>0
> for an application they think is bug free.
> On Fri, Feb 8, 2013 at 6:10 PM, Nils Loodin <nils.loodin at oracle.com
> <mailto:nils.loodin at oracle.com>> wrote:
>     It would be interesting to know the number of thrown throwables in
>     the JVM, to be able to do some high level application diagnostics /
>     statistics. A good way to put this number would be a performance
>     counter, since it is accessible both from Java and from the VM.
>     http://bugs.sun.com/__bugdatabase/view_bug.do?bug___id=8007806
>     <http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8007806>
>     http://cr.openjdk.java.net/~__nloodin/8007806/webrev.00/
>     <http://cr.openjdk.java.net/~nloodin/8007806/webrev.00/>
>     Regards,
>     Nils Loodin

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