Wildfly 11.0.0.Final org.dom4j.DocumentFactory cannot be cast to org.dom4j.DocumentFactory ------------------------------------------------------------------------------------------ Key: WFLY-11259 URL: https://issues.jboss.org/browse/WFLY-11259 Project: WildFly Issue Type: Bug Components: JPA / Hibernate Affects Versions: 11.0.0.Final Reporter: Adam Bialas Assignee: Scott Marlow Priority: Major Fix For: 17.0.0.Beta1 I have an ear file which I want to deploy to the Wildfly 11.0.0.Final. In this ear file in the lib folder I have dom4j-2.0.1.jar. One of the sub deployments (war) uses JPA (no dependencies to hibernate, just to javax.javaee-api as compile only). This sub deployment contains of course the persistence.xml file. I see in the logs that when the application server starts and loads this file the following exception is thrown: org.dom4j.DocumentFactory cannot be cast to org.dom4j.DocumentFactory and the application fails to deploy. I checked many posts and forums on the net and as far as I understand I must exclude the dom4j provided by the application server so the jar located in the lib folder of ear can be used. I created jboss-deployment-structure: <?xml version="1.0" encoding="UTF-8"?> <jboss-deployment-structure> <deployment> <exclusions> <module name="org.dom4j"/> </exclusions> </deployment> </jboss-deployment-structure> Even though I get the same exception so I suppose both jars are loaded and cause problems. I checked how class loading works on Wildfly 11.0.0 in comparison to JBoss EAP 7.1. In both cases this class is first loaded from provided 1.6.1 jar. JBoss does not load the newer version. However, Wildfly does and here is the problem.