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copied!<p>@Tom: I don't think creating a custom MarshallingHttpMessageConverter will do you any good. The built-in converter is returning you the right class (Exception class) when the service fails, but it is the <code>RestTemplate</code> that doesn't know how to return Exception class to the callee because you have specified the response type as Job class.</p> <p>I read the <a href="http://www.jarvana.com/jarvana/view/org/springframework/spring-web/3.0.2.RELEASE/spring-web-3.0.2.RELEASE-sources.jar!/org/springframework/web/client/RestTemplate.java?format=ok" rel="nofollow">RestTemplate source code</a>, and you are currently calling this API:-</p> <pre><code>public <T> T postForObject(URI url, Object request, Class<T> responseType) throws RestClientException { HttpEntityRequestCallback requestCallback = new HttpEntityRequestCallback(request, responseType); HttpMessageConverterExtractor<T> responseExtractor = new HttpMessageConverterExtractor<T>(responseType, getMessageConverters()); return execute(url, HttpMethod.POST, requestCallback, responseExtractor); } </code></pre> <p>As you can see, it returns type T based on your response type. What you probably need to do is to subclass <code>RestTemplate</code> and add a new <code>postForObject()</code> API that returns an Object instead of type T so that you can perform the <code>instanceof</code> check on the returned object.</p> <p><strong>UPDATE</strong></p> <p>I have been thinking about the solution for this problem, instead of using the built-in <code>RestTemplate</code>, why not write it yourself? I think that is better than subclassing <code>RestTemplate</code> to add a new method. </p> <p>Here's my example... granted, I didn't test this code but it should give you an idea:-</p> <pre><code>// reuse the same marshaller wired in RestTemplate @Autowired private Jaxb2Marshaller jaxb2Marshaller; public Object genericPost(String url) { // using Commons HttpClient HttpClient client = new HttpClient(); PostMethod method = new PostMethod(url); // add your data here method.addParameter("data", "your-data"); try { int returnCode = client.executeMethod(method); // status code is 200 if (returnCode == HttpStatus.SC_OK) { // using Commons IO to convert inputstream to string String xml = IOUtil.toString(method.getResponseBodyAsStream()); return jaxb2Marshaller.unmarshal(new StreamSource(new ByteArrayInputStream(xml.getBytes("UTF-8")))); } else { // handle error } } catch (Exception e) { throw new RuntimeException(e); } finally { method.releaseConnection(); } return null; } </code></pre> <p>If there are circumstances where you want to reuse some of the APIs from <code>RestTemplate</code>, you can build an adapter that wraps your custom implementation and reuse <code>RestTemplate</code> APIs without actually exposing <code>RestTemplate</code> APIs all over your code.</p> <p>For example, you can create an adapter interface, like this:-</p> <pre><code>public interface MyRestTemplateAdapter { Object genericPost(String url); // same signature from RestTemplate that you want to reuse <T> T postForObject(String url, Object request, Class<T> responseType, Object... uriVariables); } </code></pre> <p>The concrete custom rest template looks something like this:-</p> <pre><code>public class MyRestTemplateAdapterImpl implements MyRestTemplateAdapter { @Autowired private RestTemplate restTemplate; @Autowired private Jaxb2Marshaller jaxb2Marshaller; public Object genericPost(String url) { // code from above } public <T> T postForObject(String url, Object request, Class<T> responseType, Object... uriVariables) { return restTemplate.postForObject(url, request, responseType); } } </code></pre> <p>I still think this approach is much cleaner than subclassing <code>RestTemplate</code> and you have more control on how you want to handle the results from the web service calls.</p>

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