ORA-12516 error when performing JDBC operation in JBoss EAP

Issue

• When the server starts and attempts to connect to the database we see this error:

        13:45:27,744 WARN [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (JCA PoolFiller) IJ000610: Unable to fill pool: javax.resource.ResourceException: Could not create connection
...
        Caused by: oracle.net.ns.NetException: Listener refused the connection with the following error:
        ORA-12516, TNS:listener could not find available handler with matching protocol stack

         at oracle.net.ns.NSProtocol.connect(NSProtocol.java:385)
         at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1042)
         at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:301)
         ... 10 more