Cannot create PoolableConnectionFactory (Io exception: The Network Adapter could not establish the connection)

I had to go look for ojdbc compatible with version on oracle that was installed this fixed my problem, my bad was thinking one ojdbc would work for all

Just check tsnnames.ora and listener.ora files. It should not have localhost as a server. change it to hostname.

Like in tnsnames.ora

LISTENER_ORCL =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))

Replace localhost by hostname.

I had a similar error with Tomcat 8.0 / MySQL . Changing the jdbc url value from localhost to 127.0.0.1 resolved the issue.