Triaged for 10.5.2.
I believe the described behaviour is in accordance with the
documentation, so I'm closing this bug as invalid.
Here are the relevant sections from the manuals:
Reference manual, Dynamic and static properties -
> Only properties set in the following ways have the potential to be dynamic:
> * As database-wide properties
> * As system-wide properties via a Properties object in the
> application in which the Derby engine is embedded
Following from the above, since it's set as a system-wide property in
this scenario, it needs to follow the rules described in Reference
manual, Changing the system-wide properties programmatically, Using a
Properties object within an application or statement -
> In embedded mode, your application runs in the same JVM as Derby, so
> you can also set system properties within an application using a
> Properties object before loading the Derby JDBC driver.
Since the Derby JDBC driver has already been loaded in the scenario
described in this bug report, changing a system property is not
guaranteed to have any effect.