form.param("a", "<jaxbBean><value>a</value></jaxbBean>");
form.param("b", "<jaxbBean><value>b1</value></jaxbBean>");
form.param("b", "<jaxbBean><value>b2</value></jaxbBean>");
final ContainerResponse responseContext = apply(RequestContextBuilder.from("/", "POST")
.accept(MediaType.APPLICATION_XML)
.type(MediaType.APPLICATION_FORM_URLENCODED)
.entity(form)
.build()
);
JAXBBean b = (JAXBBean) responseContext.getEntity();
assertEquals("a", b.value);
}