If you have code that talks to 'ora-apps' through java, you can certainly call into that code from within the jbpm process lifecycle at various points.
there are a number of ways to setup action handlers, and other ways to integrate with the jbpm api that will let you execute snippets of java code.
refer to : http://docs.jboss.org/jbpm/v3/userguide/processmodelling.html
to integrate with any application, first understand options available for integration(like API, database connection, web service consumption). then write code for db conn/ws client/api and put this code in actionhandler class. attach this actionhandler class to "node" type activity in your process.