Unable to create initial poolsize on container


I am trying to build a docker image with a J2EE application war within (docker on ubuntu 14 linux, docker 17.04.0, Java 8, Tomcat 8, OJDBC7- The war accesses an oracle DB through SQL queries. The application war runs outside of a docker container. However, while in a container, i get the following error :

tomcat-http–5 root - java.lang.RuntimeException: java.sql.SQLException: Unable to start the Universal Connection Pool: oracle.ucp.UniversalConnectionPoolException: Failed to create initialPoolSize connections while starting a pool

Would appreciate any help on this

PS : I have placed the ojdbc jar in tomcat/lib folder of the container through the docker file