title: Send a HashMap using Jersey for REST web service
body: <p>I'm using Jersey for a REST webservice.
  I want to send a HashMap to the server, but I have a problem. This code works fine if I change parameter of the method to String, but with a HashMap, it doesn't work : </p>
  
  <pre><code>    ClientConfig config = new DefaultClientConfig();
      config.getFeatures().put(JSONConfiguration.FEATURE_POJO_MAPPING, Boolean.TRUE);
      Client client = Client.create(config);
  
      URI uri = UriBuilder.fromUri("http://localhost:8081/serviceProxy_socle-01.00.00-SNAPSHOT/services/tableauDeBord/subventions").build();
      System.out.println(uri.toString());
      WebResource service = client.resource(uri);
  
      GenericType&lt;TableauDeBordImpl&lt;CoupsDPouceImpl&gt;&gt; informationsDossier = new GenericType&lt;TableauDeBordImpl&lt;CoupsDPouceImpl&gt;&gt;(){};
  
  
      HashMap&lt;String, Object&gt; params = new HashMap&lt;String, Object&gt;();
      params.put("rne", "0240984P");
  
      TableauDeBordImpl&lt;CoupsDPouceImpl&gt; content = service
      .accept(MediaType.APPLICATION_JSON)
      .entity(params, MediaType.APPLICATION_XML)
      .type(MediaType.APPLICATION_XML).post(informationsDossier);
  </code></pre>
  
  <p>This is the Stacktrace :</p>
  
  <pre><code>Exception in thread "main" com.sun.jersey.api.client.ClientHandlerException: com.sun.jersey.api.client.ClientHandlerException: A message body writer for Java type, class java.util.HashMap, and MIME media type, application/xml, was not found
      at com.sun.jersey.client.urlconnection.URLConnectionClientHandler.handle(URLConnectionClientHandler.java:148)
      at com.sun.jersey.api.client.Client.handle(Client.java:642)
      at com.sun.jersey.api.client.WebResource.handle(WebResource.java:613)
      at com.sun.jersey.api.client.WebResource.access$300(WebResource.java:74)
      at com.sun.jersey.api.client.WebResource$Builder.post(WebResource.java:503)
      at fr.liberaccess.pool.tester.Tester.testCoupsDpouce(Tester.java:63)
      at fr.liberaccess.pool.tester.Tester.&lt;init&gt;(Tester.java:39)
      at fr.liberaccess.pool.tester.Tester.main(Tester.java:188)
  Caused by: com.sun.jersey.api.client.ClientHandlerException: A message body writer for Java type, class java.util.HashMap, and MIME media type, application/xml, was not found
      at com.sun.jersey.api.client.RequestWriter.writeRequestEntity(RequestWriter.java:299)
      at com.sun.jersey.client.urlconnection.URLConnectionClientHandler._invoke(URLConnectionClientHandler.java:203)
      at com.sun.jersey.client.urlconnection.URLConnectionClientHandler.handle(URLConnectionClientHandler.java:146)
      ... 7 more
  </code></pre>