Metro on WebSphere 7 – com.ibm.xml.xlxp2.jaxb.JAXBContextImpl incompatible exception

By mkyong | Updated: August 29, 2012

Viewed: 259 (+2 pv/w)

Tags: jax-ws metro web services websphere

Problem

Developed a SOAP web service via Metro 2.0.1 (webservices-rt.jar), integrate with Spring via jaxws-spring-1.8.jar and deployed on WebSphere Application Server (WAS) version 7.0.0.13 . See web service below :

File : UserWS.java

package com.mkyong.user.ws;
//import...
@WebService()
public class UserWS {

    private UserBo userBo;

    @WebMethod(exclude = true)
    public UserBo getUserBo() {
        return userBo;
    }

    @WebMethod(exclude = true)
    public void setUserBo(UserBo userBo) {
        this.userBo = userBo;
    }

    @WebMethod(operationName = "listUser")
    public List<User> listUser() throws SOAPException {

       return userBo.listUser();

    }
}

If everything is fine, the service is work as expected, but, when “userBo.listUser()” hit error and throwing a SOAPException back to the web service’s client :

Client get this :

Exception in thread "main" 
	javax.xml.ws.WebServiceException: No Content-type in the header!

WAS log file showing this :

Caused by: java.lang.ClassCastException: com.ibm.xml.xlxp2.jaxb.JAXBContextImpl 
	incompatible with com.sun.xml.bind.api.JAXBRIContext
	at com.sun.xml.ws.fault.SOAPFaultBuilder.<clinit>(SOAPFaultBuilder.java:561)
	at java.lang.J9VMInternals.initializeImpl(Native Method)
	at java.lang.J9VMInternals.initialize(J9VMInternals.java:200)
	... 34 more

P.S This web service is working on Tomcat, but failed on WebSphere only

Solution

The com.ibm.xml.xlxp2.jaxb.JAXBContextImpl is located at WAS_APPSERVER_PROFILE\plugins\com.ibm.ws.prereq.xlxp.jar, and Metro library, webservices-rt.jar, also contain one of the instance com.sun.xml.bind.v2.runtime.JAXBContextImpl . When exception raised, WAS is using two different instance to perform a same JAXB binding task, and raise an “java.lang.ClassCastException” incompatible exception.

To fix it, just make sure WAS is using same instance always.

1. In WAS configuration screen, set module class loader to “parent-first“.
2. In WAS folder, create a “classes” folder under WAS root folder and put webservices-rt.jar inside, for example, WAS_APPSERVER_PROFILE\classes\webservices-rt.jar.

Restart WAS instance, now WAS will load your webservices-rt.jar always. A dirty way, but it work :).