1. The bug description:
https://community.jboss.org/message/851147#851147

Named query with JPA entitymanager throws exception: java.lang.IllegalStateException: Illegal attempt to set lock mode on a non-SELECT query

2. This bug is fixed since hibernate-4.3.1:
https://hibernate.atlassian.net/browse/HHH-8756

So please Update hibernate to 4.3.1 or above according to HHH-8756 for wildfly-8.0.0-Final.

NOTE: I downloaded the latest nightly-build version, found that the hibernate version is still 4.3.0