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From Bryan Pendleton <bpendleton.de...@gmail.com>
Subject Re: Derby network server
Date Tue, 03 May 2011 13:35:20 GMT
> In the webapp:
>
> server = new NetworkServerControl();
> server.start(null);

Perhaps your webapp is trying to run these lines multiple times?

It can be very tricky to ensure that your webapp starts the
Network Server once and only once. You may be starting it
a second time, and the second instance is not succesfully
accessing the database because the first instance already has
the database open?

A possibly simpler architecture for your application is to
have an entirely separate piece of software responsible for
starting/stopping the Network Server, and then it can concentrate
on doing that once-and-only-once. So:
	1) Have a "Network Server" webapp
	2) Have your normal application webapp(s), which access
	the database as clients
	3) Have your external command-line tool(s), which access
	the database as clients
You can have as many (2) and (3) instances as you want; you
just have to ensure you have exactly one of your (1) instance.

thanks,

bryan


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