It's Sun's one, the version packed with WLS:

java version "1.4.2_08"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_08-b03)
Java HotSpot(TM) Client VM (build 1.4.2_08-b03, mixed mode)

It's pretty weird that you cannot reproduce it. I checked for some
subtle difference somewhere and I think I found the cause of the problem:

Under Connection Pool > Connections > Show Advanced Options there is
an option called "Remove Infected Connections Enabled" that I checked
by mistake. When unchecked, everything works fine again.

Not sure why such an option exists. It seems to force physical
connection to close when the pooled connection is closed.

Anyway thanks a lot for your time, my problem is solved but I'm still
available if you'd like some more information in case you want to
reproduce and/or fix this issue.

Ludovic

--- In Firebird-Java@yahoogroups.com, "Roman Rokytskyy"
<rrokytskyy@a...> wrote:

>
> > I created a connection pool + datasource via the console. The JDBC
> > driver is in WLS's classpath, not part of any EAR, WAR or RAR.
>
> Same did I... Which JVM did you run? Sun? IBM? JRockit?
>
> Roman
>