Thanks for your fast response. I have configured the persistence.xml as below: <persistence-unit name="examplePersistenceUnit"> <jta-data-source>java:/OracleDS</jta-data-source> </persistence-unit> and created Oracle database source (oracle-ds.xml) in deployed folder. <?xml version="1.0" encoding="UTF-8"?> <!-- ===================================================================== --> <!-- --> <!-- JBoss Server Configuration --> <!-- --> <!-- ===================================================================== --> <!-- $Id: oracle-ds.xml 23720 2004-09-15 14:37:40Z loubyansky $ --> <!-- ==================================================================== --> <!-- Datasource config for Oracle originally from Steven Coy --> <!-- ==================================================================== --> <local-tx-datasource> <jndi-name>OracleDS</jndi-name> <connection-url>jdbc:oracle:thin:@localhost:1521:wm</connection-url> <!-- Here are a couple of the possible OCI configurations. For more information, see http://otn.oracle.com/docs/products/oracle9i/doc_library/release2/java.92... <connection-url>jdbc:oracle:oci:@youroracle-tns-name</connection-url> or <connection-url>jdbc:oracle:oci:@(description=(address=(host=youroraclehost)(protocol=tcp)(port=1521))(connect_data=(SERVICE_NAME=yourservicename)))</connection-url> Clearly, its better to have TNS set up properly. --> <driver-class>oracle.jdbc.driver.OracleDriver</driver-class> <user-name>wm</user-name> wm <!-- Uses the pingDatabase method to check a connection is still valid before handing it out from the pool --> <!--valid-connection-checker-class-name>org.jboss.resource.adapter.jdbc.vendor.OracleValidConnectionChecker</valid-connection-checker-class-name--> <!-- Checks the Oracle error codes and messages for fatal errors --> <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.OracleExceptionSorter</exception-sorter-class-name> <!-- sql to call when connection is created <new-connection-sql>some arbitrary sql</new-connection-sql> --> <!-- sql to call on an existing pooled connection when it is obtained from pool - the OracleValidConnectionChecker is prefered <check-valid-connection-sql>some arbitrary sql</check-valid-connection-sql> --> <!-- corresponding type-mapping in the standardjbosscmp-jdbc.xml (optional) --> <type-mapping>Oracle9i</type-mapping> </local-tx-datasource> Is it enough to link to oracle database? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4209092#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...