JAXBException: ClassCastException is thrown while running a process which uses JAXB marshalling inside custom workitem handler

Issue

• Running a process with a custom workitem handler that is using JAXB marshalling fails with the following exception:

ERROR [stderr] (http-/127.0.0.1:8080-4) javax.xml.bind.JAXBException: ClassCastException: attempting to cast jar:file:/C:/BPMS/jboss-eap-6.1/modules/system/layers/base/javax/xml/bind/api/main/jboss-jaxb-api_2.2_spec-1.0.4.Final-redhat-2.jar!/javax/xml/bind/JAXBContext.class to jar:file:/C:/Program%20Files/Java/jdk1.7.0_51/jre/lib/rt.jar!/javax/xml/bind/JAXBContext.class.  Please make sure that you are specifying the proper ClassLoader.

17:56:55,620 ERROR [stderr] (http-/127.0.0.1:8080-4)    at javax.xml.bind.ContextFinder.handleClassCastException(ContextFinder.java:115)
17:56:55,620 ERROR [stderr] (http-/127.0.0.1:8080-4)    at javax.xml.bind.ContextFinder.newInstance(ContextFinder.java:251)
17:56:55,620 ERROR [stderr] (http-/127.0.0.1:8080-4)    at javax.xml.bind.ContextFinder.newInstance(ContextFinder.java:235)
17:56:55,621 ERROR [stderr] (http-/127.0.0.1:8080-4)    at javax.xml.bind.ContextFinder.find(ContextFinder.java:432)
17:56:55,621 ERROR [stderr] (http-/127.0.0.1:8080-4)    at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:637)
17:56:55,622 ERROR [stderr] (http-/127.0.0.1:8080-4)    at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:584)
17:56:55,622 ERROR [stderr] (http-/127.0.0.1:8080-4)    at com.test.CustomWorkItemHandler.executeWorkItem(CustomWorkItemHandler.java:55)

• Also while using Apache HttpClient libraries like this:

    StringEntity input = new StringEntity(request);
    input.setContentType("application/xml");
    postRequest.setEntity(input);
    HttpResponse httpResponse = httpClient.execute(postRequest);

fails with the following error:

Process Instances failed to start: java.lang.LinkageError:loader constraint violation: when resolving method "org.apache.http.client.methods.HttpPost.setEntity(Lorg/apache/http/HttpEntity;)V" the class loader (instance of org/drools/core/common/ProjectClassLoader$InternalTypesClassLoader) of the current class, com/test/jbpm6/jaxb/customworkitem/TestCustomWorkItemHandler, and the class loader (instance of org/jboss/modules/ModuleClassLoader) for resolved class, org/apache/http/client/methods/HttpPost, have different Class objects for the type tp/HttpEntity;)V used in the signature