IIOPNamingTestCase fails on IBMJDK due to ClassCastException as it is unable to find the IIOPNamingHome_Stub

IIOPNamingTestCase fails consistently when we try to run testsuite on IBMJDK after compilation with OracleJDK.
I am using the same jboss-eap.zip compiled on OracleJDK to run tests against OracleJDK for comparison and it yields clean run without any test failures.
It seems like the Stub is not visible to client as it is prepared within the jar.

Hudson job links:

run on IBM JDK:

https://hudson.qa.jboss.com/hudson/job/eap-60-as-testsuite-RHEL6-zipbuiltonoracleJDK6_testrunIBMJDK16/19/testReport/org.jboss.as.test.integration.ejb.iiop.naming/IIOPNamingTestCase/testIIOPNamingInvocation/

run on SunJDK for comparison with no failures:
http://hudson.qa.jboss.com/hudson/job/eap-60-as-testsuite-RHEL6-zipbuiltonoracleJDK6_testrunSUNJDK16/10/

Stacktrace:

Unable to load class: org.jboss.as.test.integration.ejb.iiop.naming._IIOPNamingHome_Stub

Stacktrace

java.lang.ClassCastException: Unable to load class: org.jboss.as.test.integration.ejb.iiop.naming._IIOPNamingHome_Stub
at com.ibm.rmi.javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:372)
at javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:148)
at org.jboss.as.test.integration.ejb.iiop.naming.IIOPNamingTestCase.testIIOPNamingInvocation(IIOPNamingTestCase.java:65)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)