wildfly 10: java.lang.ClassCastException: org.dom4j.DocumentFactory cannot be cast to org.dom4j.DocumentFactory

I just made all hibernate dependencies provided scope and problem solved!

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.1.0.Final</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>5.2.4.Final</version>
            <scope>provided</scope>
        </dependency>

        <!-- for JPA, use hibernate-entitymanager instead of hibernate-core -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>5.1.0.Final</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-ehcache</artifactId>
            <version>5.1.0.Final</version>
            <scope>provided</scope>
        </dependency>

add dependency dom4j to pom with scope provided

<dependency>
   <groupId>dom4j</groupId>
   <artifactId>dom4j</artifactId>
   <version>1.6.1</version>
   <scope>provided</scope>
</dependency>

I had recently the same problem with the dom4j library and Wildfly 10. I found this post (in portuguese) and replaced the dom4j library that comes with Wildfly with the one downloaded from the Maven Central, and that solved the problem.

The jar is located in $JBOSS_HOME/modules/system/layers/base/org/dom4j/main, you just replace it with the downloaded file, in my case the file was dom4j-1.6.1.jar. I suppose that if you change the version (at the time of this post this is the last version) you should also modify the module.xml file in the same folder, but I've not tried.

Previously I also tried the self-answer from h.f but didn't solved my problem.

Hope this contributes to someone with the same problem. Best regards