I would assume you're including the hibernate libraries in your WAR. If that's the case, then those need to be left out when you're deploying to WildFly as they are provided by server. Have a look at Implicit module dependencies for deployments - WildFly 8 - Project Documentation Editor and make sure you're not including any of those in your deployment.
James R. Perkins
You need to exclude the Hibernate libraries explicit with a jboss-deployment-structure.xml in you application