code: @XmlElementDecl(namespace = "http://hello.com", name = "User")
      public JAXBElement<UserImpl> createUserImpl(UserImpl value) {
          return new JAXBElement<UserImpl>(_UserImpl_QNAME, UserImpl.class, null, value);
      }
docs: Create an instance of {@link JAXBElement }{@code <}
  {@link UserImpl }{@code >}