@Test public void doesNotDefaultExceptionMappers() throws Exception { http.setRegisterDefaultExceptionMappers(false); assertThat(http.getRegisterDefaultExceptionMappers()).isFalse(); Environment environment = new Environment( "test", Jackson.newObjectMapper(), Validation.buildDefaultValidatorFactory().getValidator(), new MetricRegistry(), ClassLoader.getSystemClassLoader()); http.build(environment); for (Object singleton : environment.jersey().getResourceConfig().getSingletons()) { assertThat(singleton).isNotInstanceOf(ExceptionMapper.class); } }