Entity Beans (now know as Entities in EJB3) are an Object representation of your relational data. To put it in simple words, an entity is mapped to a table in the database. The columns of the table are mapped through the member variables of the entity. Any operations on the table are performed through this entity in Java. anonymous wrote : | so , how we can define the database that we need to use ?? ( i need to use a MySQL datastore ) You can specify this through a configuration file (Ex: persistence.xml). anonymous wrote : | if i can get more help (regarding this prob) than this forum please give me the links of such resources .... Read this http://java.sun.com/developer/technicalArticles/J2EE/jpa/ View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4137068#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...