Thank you so much Demian for your reply.
i can see that jBPM use the JPA but after i run my code it's giving me :
org.hibernate.HibernateException: /hibernate.cfg.xml not found
at org.hibernate.util.ConfigHelper.getResourceAsStream(ConfigHelper.java:170)
....
Can you give me a link where i can found how to use jBPM with Jboss/Hibernate ?