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From Dirk Verbeeck <>
Subject Re: DBCP accessed by an outside JVM
Date Wed, 05 Nov 2003 18:58:32 GMT
JNDI is provides only a way to lookup local and remote objects.
RMI is used to invoke the remote methods

So in theory you can bind a datasource in one VM (Tomcat) and do a lookup in 
your application VM and do a getConnection using RMI.
But this has approach has a problem. You cannot transfer an open connection from 
one VM to another (neither a database connection nor a simple socket).

Your solution of simply opening one database connection for each application VM 
is probably the best/easiest way (the number of application VMs will be your 
first limit and not the number of database connections).

A more advanced solution is to separate you business and presentation code 
(that’s always a good practice). Use a kind of business facade (service 
interface) and data transfer objects (value objects).
If you have this design then you can deploy your business methods (and/or data 
access objects) on tomcat and access those from your presentation/application VM 
using SOAP.

I can recommend axis ( I’m using it myself to 
connect from a swing application to a remote server. If you have a service 
interface and value objects then axis does most of the SOAP work.
You can use RMI or AltRMI ( to do 
the communication as well.

-- Dirk

Benoit Marchal wrote:

> To be more specific about what we are trying to do, we are using
> Webcream to make our java application web enable (see
> Webcream is working well but we had to make the rendering job done in a
> separate JVM that communicate with Tomcat through RMI (I don't have
> access to that communication channel). Basically each client that
> connect to our Web enabled java application will induce the creation of
> a separate JVM. The problem is that we need to make connection with the
> db from within the separate JVMs. Defining a new pool for each JVM is
> not an option (too many connection opened then) and in that case using
> no connection pool at all is even better. 
> I have tried to communicate with the Tomcat DBCP through JNDI but I
> haven't been successful so far (I am not an expert in JNDI anyway) 
> Benoit 

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