### Question:
RestAuthX509CallbackHandler extends AbstractRestAuthCallbackHandler<X509CertificateCallback> { public String getCallbackClassName() { return CALLBACK_NAME; }  boolean updateCallbackFromRequest(HttpServletRequest request,
            HttpServletResponse response, X509CertificateCallback callback); X509CertificateCallback handle(HttpServletRequest request, HttpServletResponse response,
            JsonValue postBody, X509CertificateCallback originalCallback); String getCallbackClassName(); JsonValue convertToJson(X509CertificateCallback callback, int index); X509CertificateCallback convertFromJson(X509CertificateCallback callback, JsonValue jsonCallback);  }### Answer:
@Test public void shouldGetCallbackClassName() { String callbackClassName = restAuthX509CallbackHandler.getCallbackClassName(); assertEquals(X509CertificateCallback.class.getSimpleName(), callbackClassName); }