post json data in javascript to java rest service

I am developing a phonegap application , in that I need to pass JSON data from my phonegap app to java rest service. I am using jquery mobile.

My Javscript:

$.ajax({
       type: "POST",
      // url: "http://ift.tt/1KEwLKs",
       url: "http://localhost:8090/CrunchifyTutorials/api/crunchifyService",
       dataType: "json",
       //data: {identity: <username from form>, password: <password from form>},
       data: str,
       success: function(data) {
        // obj = JSON.parse(data);

         alert("data" +data);

       },
       error: function(e) {
         alert('Error: ' + e.message);
       }
    });

My Java Rest services:

@Path("/")
public class CrunchifyRESTService 
{

    @POST
    @Path("/crunchifyService")
    @Consumes(MediaType.APPLICATION_JSON)

  public Response crunchifyREST(InputStream incomingData) 
    {

        StringBuilder crunchifyBuilder = new StringBuilder();

        try {
            BufferedReader in = new BufferedReader(new InputStreamReader(incomingData));
            String line = null;
            while ((line = in.readLine()) != null) {
                crunchifyBuilder.append(line);
            }

        } catch (Exception e) {
            System.out.println("Error Parsing: - ");
        }

        System.out.println("Data Received: " + crunchifyBuilder.toString());

        // return HTTP response 200 in case of success
        return Response.status(200).entity(crunchifyBuilder.toString()).build();
    }
}  

can you suggest me how to do it.