For EAP edition 4.2 is not release to use with JDK6.
First version JDK6 compatible or approved is EAP 4.3.0
Basically its not a JDK issue it happens in JBoss4.2 too. The reason is a non-compliance issue in JSF 1.2.9 implementation of Mojara. What I request you is to include the JSF 1.2.12 jars or higher instead.