Currently i am working with jsf using hibernate.I dont know how to retreive data from table present in the database.Can anyone help with an example code.
Thanks in advance

No problem, you must edit the hibernate configuration file (hibernate.cfg.xml), and change the database properties. At this time i use mssql, so i don't have oracle example, but i find this for you:

<session-factory>
<property name="connection.username">xxxxx</property>
<property name="connection.url">jdbc:oracle:thin:@localhost:1521:</property>
<property name="dialect">org.hibernate.dialect.Oracle9Dialect</property>
<property name="connection.password">xxxxx</property>
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
</session-factory>

You must edit the values in this example. After this, all the hql queries runs in the oracle database.