What does the ORA-12154 error code in server log indicates ?

Issue

• While running a JBoss instance which has an Oracle DataSource, Why the following exception is observed in the server logs intermittently?

WARN  [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (ajp-example.com/10.10.10.10:8080-21) IJ000604: Throwable while attempting to get a new connection: null: javax.resource.ResourceException: Could not create connection

Caused by: oracle.net.ns.NetException: Listener refused the connection with the following error:
ORA-12514, TNS:listener does not currently know of service requested in connect descriptor 
    at oracle.net.ns.NSProtocol.connect(NSProtocol.java:395) [ojdbc6.jar:11.2.0.3.0]
    at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1102) [ojdbc6.jar:11.2.0.3.0]
    at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:320) [ojdbc6.jar:11.2.0.3.0]
    ... 60 more