Spring restTemplate NoClassDefFoundError

I have a NoClassDefFoundError when using Spring restTemplate for the code below at line messageConverters.add(new MappingJackson2HttpMessageConverter());

can anyone know what I miss?

RestTemplate restTemplate = new RestTemplate();
List<HttpMessageConverter<?>> messageConverters = new   ArrayList<HttpMessageConverter<?>>();
messageConverters.add(new MappingJackson2HttpMessageConverter());
restTemplate.setMessageConverters(messageConverters);
ResponseEntity<String> responseEntity = restTemplate
            .exchange(
                    "http://ift.tt/1xkRZKe",
                    HttpMethod.GET, requestEntity, String.class);

error: exception in thread "main" java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/ObjectMapper at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.(MappingJackson2HttpMessageConverter.java:62)