Since I haven't received an answer to my question. I've decided to try and find a different solution.
So, I've got a Java EE application that is deployed on a JBoss server and I'm asking if there's a way to initialize a database with some data, before the user starts interacting with the application. Apparently, a singleton bean that is executed at start-up is a problem (see my other question)
I've answered on your questions here Problems with using a stateful session bean from a singleton bean