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From John Embretsen <John.Embret...@Sun.COM>
Subject Re: derby Static refs to log objects
Date Wed, 23 May 2007 10:10:01 GMT
Robert Harryman wrote:

> Next I added  classloading of the embedded derby driver, did a shutdown 
> of the database and unregistered the
> driver. Using jmap/jhat (jdk 1.6) I see that all my objects are being 
> kept alive and that there are a lot
> of derby static refs around to java.util.logging.Logger. This leak will 
> force me to bounce the container during
> redeploy since PermGen will eventually exhaust and cause an out of 
> memory condition.
> 
> Is this a known problem? Does derby/javaDB have a bug against static 
> references to log objects?

As far as I know, Derby does not use the java.util.logging package at all, so 
your findings puzzle me. Then again, maybe I am misunderstanding what you are 
asking...

(Derby (and Java DB) versions up to and including 10.2 support J2SE 1.3, which 
does not include the logging API).

Do you get similar results (references to java.util.logging.Logger) if you run 
the following query in jhat's OQL tool?

select referrers(f) from java.util.logging.Logger f

(lists Java objects that hold reference to java.util.logging.Logger)

or for example

select 
referees(heap.findClass("org.apache.derby.impl.services.monitor.BaseMonitor"))

(returns an array of Java objects to which the given Java object directly refers 
to).



-- 
John



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