Android REST webservices

I have a code which works perfectly on the java project but when i use the same on the android project it throws error here is the code .(Note i cannot share link and parameters, problem is NOT there . link is right . the code is working i am getting result in java project in eclipse but same in android project fails )

try{
        Client client=Client.create();  
        WebResource webResource2 = client.resource("some...link");

        WSDetPojo wsdetpojo = new WSDetPojo(); // some class
        wsdetpojo.parameter1("parameter1");
        wsdetpojo.parameter2("parameter2");
        wsdetpojo.parameter3("parameter3");
        wsdetpojo.parameter4("parameter4");


        ObjectMapper om=new ObjectMapper();

        ClientResponse response2 = webResource2.type("application/json")
        .post(ClientResponse.class,om.writeValueAsString(wsdetpojo)); // here is the problem <==

        System.out.println("response of sms ==> "+response2);
        if (response2.getStatus() != 201) 
        {
            throw new RuntimeException("Failed : HTTP error code : "+ response2.getStatus());

        }

        String output2 = response2.getEntity(String.class);
        System.out.println("output :\n" +output2);

    }catch(Exception ex){
        ex.printStackTrace();
    }

Now here is the error which i get when i run it on android

java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.Object javax.ws.rs.ext.RuntimeDelegate$HeaderDelegate.fromString(java.lang.String)' on a null object reference
    at javax.ws.rs.core.MediaType.valueOf(MediaType.java:119)
    at com.sun.jersey.api.client.PartialRequestBuilder.type(PartialRequestBuilder.java:92)
    at com.sun.jersey.api.client.WebResource.type(WebResource.java:347)
    at co.example.punerto.classes.NicClient.sendData(NicClient.java:43)
    at com.example.punerto.Activity.ActivityLearnLicAppointment_Tab6$uploadFrom.doInBackground(ActivityLearnLicAppointment_Tab6.java:303)
    at com.example.punerto.Activity.ActivityLearnLicAppointment_Tab6$uploadFrom.doInBackground(ActivityLearnLicAppointment_Tab6.java:1)
    at android.os.AsyncTask$2.call(AsyncTask.java:288)
    at java.util.concurrent.FutureTask.run(FutureTask.java:237)
    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
    at java.lang.Thread.run(Thread.java:818)

Please help !! Stuck on this spent 8 hours already . I also tried alternative did not worked !! If you have some alternative for this please do let me know.