title: A message body reader for Java class java.util.List, and Java type java.util.List<>, and MIME media type text/html was not found
body: <p>I got this error </p>
  
  <pre><code>A message body reader for Java class java.util.List, and Java type java.util.List&lt;Entities.service.GroupU&gt;, and MIME media type text/html was not found
  </code></pre>
  
  <p>when I execute this code</p>
  
  <pre><code> GroupUClient client1 = new GroupUClient();
          ClientResponse response = client1.findAll_XML(ClientResponse.class);
  
          GenericType&lt;List&lt;GroupU&gt;&gt; genericType = new GenericType&lt;List&lt;GroupU&gt;&gt;() {
          };
  // Returns an ArrayList of Players from the web service
          data = new ArrayList&lt;GroupU&gt;();
          data = (response.getEntity(genericType));
  </code></pre>
  
  <p>what is the problem ? </p>