I suppose that you have a problem with the JDBC driver, you have to use the correct one for the JVM and the Oracle version.
1.currently iam using oracle.jdbc.driver.OracleDriver. I hope this is ok.
2.able to connect /ping to the specified host.
But still getting the same prob.
By Driver I meant the version of the JAR that you add to the lib directory, e.g. ojdbc6.jar.
It must work with the Oracle 11 version, if you use a old one e.g. classes12.jar it wont work and might produce strange effects.
currently deplojed jar is ojdbc14.jar
Depend on you Java version (5 or 6) you have to use ojdbc5.jar or ojdbc6.jar. I suppose ojdbc14 will not work with Oracle11g
See Oracle page