OK, I looked at your post first and got the impression that you wanted to set up a connection pool, but then you mention that you want the application is in oracle, but the jbpm database is in mysql?
How is your application interacting with jbpm? In embedded mode? If so, is there a particular reason why the two data is being kept in separate databases(coz it's much easier if it is one).
With the two database approach, you need to co-ordinate transactions using distributed transactions across both the databases.
Does JBPM provides any provision for application database connetion pooling across JBPM process instances?
I am not sure I understand the question there, across JBPM process instances? Coz, all JBPM process instances will reside in the same database.