JAXB marshalling gets "UnmarshalException: unexpected element (uri:"", local:"xxxxx")" in RESTEasy client on EAP

Issue

• RESTEasy client is not able to convert the received JSON response into JSON object.
• My Resource code:

    @GET
    @Path("/customer/{id}")
    public Response getCustomer(@PathParam("id") int id) {
        Customer customer = ...
        return Response.ok(customer).build();
    }

• Customer Class:

@XmlRootElement(name = "customer")
@XmlType(propOrder = {"firstName", "lastName", ...})
public class Customer {
    private int id;
    private String firstName;
    private String lastName;
    ...

• Client code:

    @Test
    public void getCustomer() throws Exception {
        ClientRequest request = new ClientRequest("http://localhost:8080/sample/customer/1");
        ClientResponse<Customer> response = request.get(Customer.class);
        Customer customer = response.getEntity();
        ...

• The exception I am getting:

org.jboss.resteasy.plugins.providers.jaxb.JAXBUnmarshalException: javax.xml.bind.UnmarshalException
 - with linked exception:
[com.sun.istack.SAXParseException2; columnNumber: 0; unexpected element (uri:"", local:"id"). Expected elements are <{}customer>]
    at org.jboss.resteasy.plugins.providers.jaxb.AbstractJAXBProvider.readFrom(AbstractJAXBProvider.java:119)
    at org.jboss.resteasy.core.interception.MessageBodyReaderContextImpl.proceed(MessageBodyReaderContextImpl.java:105)
    at org.jboss.resteasy.plugins.interceptors.encoding.GZIPDecodingInterceptor.read(GZIPDecodingInterceptor.java:63)
    at org.jboss.resteasy.core.interception.MessageBodyReaderContextImpl.proceed(MessageBodyReaderContextImpl.java:108)
    at org.jboss.resteasy.client.core.BaseClientResponse.readFrom(BaseClientResponse.java:433)
    at org.jboss.resteasy.client.core.BaseClientResponse.getEntity(BaseClientResponse.java:377)
    at org.jboss.resteasy.client.core.BaseClientResponse.getEntity(BaseClientResponse.java:338)
    at com.sample.app.test.RestEasyClientTest.getCustomer(RestEasyClientTest.java:86)
    ...