title: String cannot be cast to org.springframework.http.ResponseEntity
body: <p>While using the following code, I'm getting a <code>ClassCastException: String
  cannot be cast to org.springframework.http.ResponseEntity</code>.</p>
  
  <pre><code>@Autowired
  private  ClientService clientService;
  
  public void methodA() {
      String url = ...
      ResponseEntity&lt;String&gt; resEntity = clientService.callService(url);
  }
  </code></pre>