Datasource initialization fails due to ClassNotFoundException for oracle.security.pki.OraclePKIProvider class in EAP 6?

Issue

• Datasource is not getting initialized and getting the following logs which says the driver is not initializing due to ClassNotFoundException:oracle.security.pki.OraclePKIProvider ERROR. what could be the cause of this issue?

Nov 13 04:41:45,284 ERROR [org.jboss.as.controller.management-operation] (ServerService Thread Pool -- 29) JBAS014612: Operation ("add") failed - address: ([
    ("subsystem" => "datasources"),
    ("jdbc-driver" => "oracle")
]): java.util.ServiceConfigurationError: java.sql.Driver: Provider oracle.jdbc.OracleDriver could not be instantiated
        at java.util.ServiceLoader.fail(ServiceLoader.java:224) [rt.jar:1.7.0_55]
        at java.util.ServiceLoader.access$100(ServiceLoader.java:181) [rt.jar:1.7.0_55]
        at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:377) [rt.jar:1.7.0_55]
        at java.util.ServiceLoader$1.next(ServiceLoader.java:445) [rt.jar:1.7.0_55]
        at org.jboss.as.connector.subsystems.datasources.JdbcDriverAdd.performRuntime(JdbcDriverAdd.java:117)
        at org.jboss.as.controller.AbstractAddStepHandler$1.execute(AbstractAddStepHandler.java:50) [jboss-as-controller-7.2.1.Final-redhat-10.jar:7.2.1.Final-redhat-10
]
        at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:440) [jboss-as-controller-7.2.1.Final-redhat-10.jar:7.2.1.Final-re
dhat-10]
        at org.jboss.as.controller.AbstractOperationContext.doCompleteStep(AbstractOperationContext.java:322) [jboss-as-controller-7.2.1.Final-redhat-10.jar:7.2.1.Final
-redhat-10]
        at org.jboss.as.controller.AbstractOperationContext.completeStepInternal(AbstractOperationContext.java:229) [jboss-as-controller-7.2.1.Final-redhat-10.jar:7.2.1
.Final-redhat-10]
        at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:224) [jboss-as-controller-7.2.1.Final-redhat-10.jar:7.2.1.Fin
al-redhat-10]
        at org.jboss.as.controller.ParallelBootOperationStepHandler$ParallelBootTask.run(ParallelBootOperationStepHandler.java:334) [jboss-as-controller-7.2.1.Final-red
hat-10.jar:7.2.1.Final-redhat-10]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_55]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_55]
        at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_55]
        at org.jboss.threads.JBossThread.run(JBossThread.java:122) [jboss-threads-2.1.0.Final-redhat-1.jar:2.1.0.Final-redhat-1]
Caused by: java.lang.NoClassDefFoundError: oracle/security/pki/OraclePKIProvider
        at java.lang.Class.getDeclaredConstructors0(Native Method) [rt.jar:1.7.0_55]
        at java.lang.Class.privateGetDeclaredConstructors(Class.java:2493) [rt.jar:1.7.0_55]
        at java.lang.Class.getConstructor0(Class.java:2803) [rt.jar:1.7.0_55]
        at java.lang.Class.newInstance(Class.java:345) [rt.jar:1.7.0_55]
        at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:373) [rt.jar:1.7.0_55]
        ... 12 more
Caused by: java.lang.ClassNotFoundException: oracle.security.pki.OraclePKIProvider from [Module "oracle.jdbc:main" from local module loader @63b550b5 (finder:
 local module finder @14c5ce37 (roots: /path-up-to/jboss-eap-6.1.1/modules,/path-up-to/jboss-eap-6.1.1/modules/system/layers/base,/other/modules))]
        at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:196) [jboss-modules.jar:1.2.2.Final-redhat-1]
        at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:444) [jboss-modules.jar:1.2.2.Final-redhat-1]
        at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:432) [jboss-modules.jar:1.2.2.Final-redhat-1]
        at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:374) [jboss-modules.jar:1.2.2.Final-redhat-1]
        at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:119) [jboss-modules.jar:1.2.2.Final-redhat-1]
        ... 17 more