Hi Yogesh!
I am not sure exactly what you are asking. As far as I know, jBPM 5.4 does not use any kind of databse by default, not even H2. I think the human task service uses H2, but the jBPM engine itself does not. Now, that said, I've read it is possible to get it to use a database, but have not figured it out yet. Some discussions and articles I've read talk about doing persistence through the JBPMHelper class.
Post back here if you get it working. :D